alter_generic regression test cannot run concurrently with privileges test.

... because the latter plays games with the privileges for language SQL.
It looks like running alter_generic in parallel with "misc" is OK though.

Also, adjust serial_schedule to maintain the same test ordering (up to
parallelism) as parallel_schedule.

src/test/regress/parallel_schedule

@@ -83,9 +83,13 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 # Another group of parallel tests
 # ----------
-test: privileges security_label collate alter_generic
+test: privileges security_label collate
+
+# ----------
+# Another group of parallel tests
+# ----------
+test: misc alter_generic
 
-test: misc
 # rules cannot run concurrently with any test that creates a view
 test: rules
 # event triggers cannot run concurrently with any test that runs DDL

src/test/regress/serial_schedule

@@ -51,7 +51,6 @@ test: create_function_1
 test: create_type
 test: create_table
 test: create_function_2
-test: create_function_3
 test: copy
 test: copyselect
 test: create_misc
@@ -59,6 +58,7 @@ test: create_operator
 test: create_index
 test: create_view
 test: create_aggregate
+test: create_function_3
 test: create_cast
 test: constraints
 test: triggers
@@ -95,6 +95,7 @@ test: privileges
 test: security_label
 test: collate
 test: misc
+test: alter_generic
 test: rules
 test: event_trigger
 test: select_views
@@ -125,7 +126,6 @@ test: without_oid
 test: conversion
 test: truncate
 test: alter_table
-test: alter_generic
 test: sequence
 test: polymorphism
 test: rowtypes