Fix upgrade test: build default install SQL from HEAD, not initial commit

[jrgemignani]

…mmit

The upgrade test previously built age--.sql from the initial version-bump commit, meaning CREATE EXTENSION installed 'day-one' SQL. This caused all 31 non-upgrade regression tests to run WITHOUT SQL functions added after the version bump (e.g., age_invalidate_graph_cache, age_prepare_pg_upgrade, age_vertex_stats, etc.). These functions were never registered in pg_proc, so features depending on them (like VLE cache invalidation triggers) were silently disabled during testing.

Fix by inverting the upgrade test direction:

Before (installs incomplete SQL, upgrades to complete):
age--1.7.0.sql built from version-bump commit (incomplete)
age--1.7.0_upgrade_test.sql built from HEAD (complete)
age--1.7.0--1.7.0_upgrade_test.sql stamped from template
Test: CREATE EXTENSION age -> data -> ALTER EXTENSION UPDATE TO '1.7.0_upgrade_test'

After (installs complete SQL, upgrades from synthetic initial):
age--1.7.0.sql built from HEAD (complete)
age--1.7.0_initial.sql built from version-bump commit (synthetic)
age--1.7.0_initial--1.7.0.sql stamped from template
Test: CREATE EXTENSION age VERSION '1.7.0_initial' -> data -> ALTER EXTENSION UPDATE TO '1.7.0'

This ensures:

• All 31 non-upgrade tests run with every SQL function registered
• The upgrade template is still validated (initial -> current)
• The test ends at the default version (clean state for drop test)
• Tarball builds (no git) work identically (cat sql/sql_files)
• All synthetic files are cleaned up after the test

Makefile changes:

• age_sql rule: cat current HEAD sql/sql_files (was: git show from commit)
• New age_init_sql rule: git show from version-bump commit
• age_upgrade_test_sql: stamps template as INIT->CURR (was CURR->NEXT)
• EXTRA_CLEAN, _install_upgrade_test_files: updated filenames
• Removed AGE_NEXT_VER, age_next_sql; added AGE_INIT_VER, age_init_sql

Test SQL changes:

• Step 3: CREATE EXTENSION age VERSION '' (was: CREATE EXTENSION age)
• Step 6: ALTER EXTENSION age UPDATE TO default_version (was: LIKE '%_upgrade_test')
• Step 7: Check installed = default (was: installed <> default)
• Comments updated throughout to reflect inverted direction

All 32 regression tests pass.

modified: Makefile
modified: regress/expected/age_upgrade.out
modified: regress/sql/age_upgrade.sql

[MuhammadTahaNaveed]

Verified. Fixes the new functions missing in age-x.x.x.sql file.