Remove new locale dependency in regproc regression test.

The modified error message for regcollationin failure includes
the database encoding, which it should've occurred to me is a
portability hazard for the regression tests.  Adjust the test
so the expected output doesn't include that.

In passing, fix a comment typo introduced in b8c0ffbd2.

Per buildfarm.

src/backend/utils/adt/domains.c

@@ -127,7 +127,7 @@ domain_state_setup(Oid domainType, bool binary, MemoryContext mcxt)
  * execExpr*.c, but we execute each constraint separately, rather than
  * compiling them in-line within a larger expression.
  *
- * If escontext points to an ErrorStateContext, any failures are reported
+ * If escontext points to an ErrorSaveContext, any failures are reported
  * there, otherwise they are ereport'ed.  Note that we do not attempt to do
  * soft reporting of errors raised during execution of CHECK constraints.
  */

src/test/regress/expected/regproc.out

@@ -268,10 +268,10 @@ SELECT regtype('ng_catalog.int4');
 ERROR:  schema "ng_catalog" does not exist
 LINE 1: SELECT regtype('ng_catalog.int4');
                        ^
+\set VERBOSITY sqlstate \\ -- error message is encoding-dependent
 SELECT regcollation('ng_catalog."POSIX"');
-ERROR:  collation "ng_catalog.POSIX" for encoding "SQL_ASCII" does not exist
-LINE 1: SELECT regcollation('ng_catalog."POSIX"');
-                            ^
+ERROR:  42704
+\set VERBOSITY default
 -- schemaname not applicable
 SELECT regrole('regress_regrole_test');
 ERROR:  role "regress_regrole_test" does not exist
@@ -454,10 +454,10 @@ SELECT pg_input_error_message('ng_catalog.pg_class', 'regclass');
  relation "ng_catalog.pg_class" does not exist
 (1 row)
 
-SELECT pg_input_error_message('ng_catalog."POSIX"', 'regcollation');
-                        pg_input_error_message                        
-----------------------------------------------------------------------
- collation "ng_catalog.POSIX" for encoding "SQL_ASCII" does not exist
+SELECT pg_input_is_valid('ng_catalog."POSIX"', 'regcollation');
+ pg_input_is_valid 
+-------------------
+ f
 (1 row)
 
 SELECT pg_input_error_message('no_such_config', 'regconfig');

src/test/regress/sql/regproc.sql

@@ -74,7 +74,9 @@ SELECT regproc('ng_catalog.now');
 SELECT regprocedure('ng_catalog.abs(numeric)');
 SELECT regclass('ng_catalog.pg_class');
 SELECT regtype('ng_catalog.int4');
+\set VERBOSITY sqlstate \\ -- error message is encoding-dependent
 SELECT regcollation('ng_catalog."POSIX"');
+\set VERBOSITY default
 
 -- schemaname not applicable
 
@@ -124,7 +126,7 @@ SELECT to_regnamespace('foo.bar');
 -- Test soft-error API
 
 SELECT pg_input_error_message('ng_catalog.pg_class', 'regclass');
-SELECT pg_input_error_message('ng_catalog."POSIX"', 'regcollation');
+SELECT pg_input_is_valid('ng_catalog."POSIX"', 'regcollation');
 SELECT pg_input_error_message('no_such_config', 'regconfig');
 SELECT pg_input_error_message('no_such_dictionary', 'regdictionary');
 SELECT pg_input_error_message('Nonexistent', 'regnamespace');