Organize and deduplicate statistics import tests.

yb conflict resolutions:

- src/test/regress/expected/stats_import.out
  [Unknown context]
    >-        0 |        -1 |             0 |            0
    >+        1 |         0 |             0 |            0
    <-        0 |        -1 |             0
    <+        1 |         0 |             0
    >-SELECT relpages, reltuples, relallvisible, relallfrozen
    <-SELECT relpages, reltuples, relallvisible
    >- relpages | reltuples | relallvisible | relallfrozen
    >-----------+-----------+---------------+--------------
    >-        0 |        -1 |             0 |            0
    <- relpages | reltuples | relallvisible
    <-----------+-----------+---------------
    <-        0 |        -1 |             0

  >@@ -182,13 +153,12 @@ FROM pg_class
  <@@ -181,13 +152,12 @@ FROM pg_class
    >-       17 |       400 |             4 |            2
    >+      -17 |       400 |             4 |            2
    <-       17 |       400 |             4
    <+      -17 |       400 |             4

  >@@ -1006,20 +981,6 @@ SELECT 3, 'tre', (3, 3.3, 'TRE', '2003-03-03', NULL)::stats_import.complex_type,
  <@@ -981,19 +956,6 @@ SELECT 3, 'tre', (3, 3.3, 'TRE', '2003-03-03', NULL)::stats_import.complex_type,
    >-    'relallvisible', '0'::integer,
    >-    'relallfrozen', '0'::integer
    <-    'relallvisible', '0'::integer

  >@@ -1207,160 +1179,17 @@ SELECT pg_catalog.pg_clear_attribute_stats(
  <@@ -1181,154 +1154,17 @@ SELECT pg_catalog.pg_clear_attribute_stats(
    >-        'relallvisible', 4::integer,
    >-        'relallfrozen', 3::integer);
    <-        'relallvisible', 4::integer);
    >-        'relallvisible', 4::integer,
    >-        'relallfrozen', 3::integer);
    <-        'relallvisible', 4::integer);
    >-        'relallvisible', 4::integer,
    >-        'relallfrozen', 3::integer);
    <-        'relallvisible', 4::integer);
    >-        'relallvisible', 4::integer,
    >-        'relallfrozen', 3::integer);
    <-        'relallvisible', 4::integer);
    >-        'relallfrozen', 3::integer,
    >-        'relallvisible', 4::integer,
    >-        'relallfrozen', 3::integer);
    <-        'relallvisible', 4::integer);

    Cause: Missing 99f8f3f: `relallfrozen` was introduced.
    Resolution: Feature does not exist in pg15

  >@@ -480,7 +536,7 @@ AND inherited = false
  <@@ -455,7 +511,7 @@ AND inherited = false
    >- stats_import | test      | id      | f         |       0.9 |        10 |       -0.4 |                  |                   |                  |             |                   |                        |                      |                        |                  |
    >+ stats_import | test      | id      | f         |      0.23 |         5 |        0.6 |                  |                   |                  |             |                   |                        |                      |                        |                  |
    <- stats_import | test      | id      | f         |       0.8 |         9 |       -0.9 |                  |                   |                  |             |                   |                        |                      |                        |                  |
    <+ stats_import | test      | id      | f         |      0.22 |         5 |        0.6 |                  |                   |                  |             |                   |                        |                      |                        |                  |

  >@@ -508,18 +560,15 @@ AND inherited = false
  <@@ -483,18 +535,15 @@ AND inherited = false
    >+ stats_import | test      | id      | f         |      0.23 |         5 |        0.6 | {2,1,3}          | {0.3,0.25,0.05}   |                  |             |                   |                        |                      |                        |                  |
    <+ stats_import | test      | id      | f         |      0.22 |         5 |        0.6 | {2,1,3}          | {0.3,0.25,0.05}   |                  |             |                   |                        |                      |                        |                  |
    Cause: Missing ccff2d2: Some ERRORs were converted to softer WARNINGS.
    Resolution: pg15 values are not updated due to the ERROR.

- src/test/regress/sql/stats_import.sql
  [Unknown context]
    >-SELECT relpages, reltuples, relallvisible, relallfrozen
    <-SELECT relpages, reltuples, relallvisible

  >@@ -686,16 +675,6 @@ SELECT 4, 'four', NULL, int4range(0,100), NULL;
  <@@ -674,15 +663,6 @@ SELECT 4, 'four', NULL, int4range(0,100), NULL;
    >-    'relallvisible', '0'::integer,
    >-    'relallfrozen', '0'::integer
    <-    'relallvisible', '0'::integer

  >@@ -848,160 +827,24 @@ FROM pg_statistic s
  <@@ -835,154 +815,24 @@ FROM pg_statistic s
    >-        'relallvisible', 4::integer,
    >-        'relallfrozen', 3::integer);
    <-        'relallvisible', 4::integer);
    >-        'relallvisible', 4::integer,
    >-        'relallfrozen', 3::integer);
    <-        'relallvisible', 4::integer);
    >-        'relallvisible', 4::integer,
    >-        'relallfrozen', 3::integer);
    <-        'relallvisible', 4::integer);
    >-        'relallvisible', 4::integer,
    >-        'relallfrozen', 3::integer);
    <-        'relallvisible', 4::integer);
    >-        'relallfrozen', 3::integer,
    >-        'relallvisible', 4::integer,
    >-        'relallfrozen', 3::integer);
    <-        'relallvisible', 4::integer);
    Cause: Missing 99f8f3f: `relallfrozen` was introduced.
    Resolution: Feature does not exist in pg15

Author: Corey Huinker <corey.huinker@gmail.com>
Reported-by: Melanie Plageman <melanieplageman@gmail.com>
Discussion: https://postgr.es/m/CAAKRu_bWEqUfxhODfJ-XbZC75vq=P6DYOKK6biyey=yM1Ah3Hg@mail.gmail.com
Discussion: https://postgr.es/m/CADkLM=f1n2_Vomq0gKab7xdxDHmJGgn=DE48P8fzQOp3Mrs1Qg@mail.gmail.com
(cherry picked from commit 1d33de9)

Author: jeff-davis