MDEV-18444 ROW_FORMAT=COMPRESSED unnecessarily requires NOCOPY for INSTANT operation

instant_alter_column_possible(): allow non-rebuilding operations for
ROW_FORMAT=COMPRESSED

Author: kevgs

mysql-test/suite/innodb/r/instant_alter_bugs.result

@@ -128,3 +128,21 @@ HANDLER h READ `PRIMARY` PREV WHERE 0;
 pk	f1	f2	f3	f4	f5	f6	f7	f8	filler
 HANDLER h CLOSE;
 DROP TABLE t1;
+create table t (
+a varchar(9),
+b int,
+c int,
+row_start bigint unsigned generated always as row start invisible,
+row_end bigint unsigned generated always as row end invisible,
+period for system_time (row_start, row_end)
+) engine=innodb row_format=compressed with system versioning;
+insert into t values (repeat('a', 9), 1, 1);
+set @@system_versioning_alter_history = keep;
+alter table t modify a varchar(10), algorithm=instant;
+alter table t change b bb int, algorithm=instant;
+alter table t modify c int without system versioning, algorithm=instant;
+set @@system_versioning_alter_history = error;
+check table t;
+Table	Op	Msg_type	Msg_text
+test.t	check	status	OK
+drop table t;

mysql-test/suite/innodb/t/instant_alter_bugs.test

@@ -136,3 +136,21 @@ HANDLER h CLOSE;
 DROP TABLE t1;
 --let $datadir= `select @@datadir`
 --remove_file $datadir/test/load.data
+
+
+create table t (
+  a varchar(9),
+  b int,
+  c int,
+  row_start bigint unsigned generated always as row start invisible,
+  row_end bigint unsigned generated always as row end invisible,
+  period for system_time (row_start, row_end)
+) engine=innodb row_format=compressed with system versioning;
+insert into t values (repeat('a', 9), 1, 1);
+set @@system_versioning_alter_history = keep;
+alter table t modify a varchar(10), algorithm=instant;
+alter table t change b bb int, algorithm=instant;
+alter table t modify c int without system versioning, algorithm=instant;
+set @@system_versioning_alter_history = error;
+check table t;
+drop table t;

storage/innobase/handler/handler0alter.cc

@@ -1465,9 +1465,6 @@ instant_alter_column_possible(
 	const TABLE*			table,
 	const TABLE*			altered_table)
 {
-	if (!ib_table.supports_instant()) {
-		return false;
-	}
 #if 1 // MDEV-17459: adjust fts_fetch_doc_from_rec() and friends; remove this
 	if (ib_table.fts) {
 		return false;
@@ -1521,6 +1518,8 @@ instant_alter_column_possible(
 		    && alter_options_need_rebuild(ha_alter_info, table)) {
 			return false;
 		}
+	} else if (!ib_table.supports_instant()) {
+		return false;
 	}
 
 	/* At the moment, we disallow ADD [UNIQUE] INDEX together with