Leave out some object files from mock test programs.

This cuts down the size of each test program from about 45 MB to 41 MB on
my laptop, with debug-enabled builds. That should help to speed up the tests
a little bit.

src/backend/mock.mk

@@ -21,14 +21,87 @@ MOCK_LIBS := -ldl $(filter-out -lpgport -ledit, $(LIBS)) $(LDAP_LIBS_BE)
 # These files are not linked into test programs.
 EXCL_OBJS=\
 	src/backend/main/main.o \
+	src/backend/access/transam/rmgr.o \
+	src/backend/utils/fmgrtab.o \
 	src/backend/gpopt/%.o \
 	src/backend/gpopt/config/%.o \
 	src/backend/gpopt/relcache/%.o \
 	src/backend/gpopt/translate/%.o \
-	src/backend/gpopt/utils/%.o
+	src/backend/gpopt/utils/%.o \
+
+# More files that are not linked into test programs. There's no particular
+# reason these couldn't be linked into, if necessary, but currently none of
+# the tests need these, so better to leave them out to cut down on the size
+# of the test programs. Feel free to link them back (i.e. remove them from
+# this exclusion list) as needed.
+EXCL_OBJS+=\
+	src/backend/access/gist/%.o \
+	src/backend/access/gin/%.o \
+	src/backend/access/hash/hash.o \
+	src/backend/access/hash/hashinsert.o \
+	src/backend/access/hash/hashovfl.o \
+	src/backend/access/hash/hashpage.o \
+	src/backend/access/hash/hashsearch.o \
+	src/backend/access/hash/hashutil.o \
+	\
+	src/backend/utils/adt/ascii.o \
+	src/backend/utils/adt/cash.o \
+	src/backend/utils/adt/char.o \
+	src/backend/utils/adt/complex_type.o \
+	src/backend/utils/adt/domains.o \
+	src/backend/utils/adt/enum.o \
+	src/backend/utils/adt/geo_ops.o \
+	src/backend/utils/adt/geo_selfuncs.o \
+	src/backend/utils/adt/gp_dump_oids.o \
+	src/backend/utils/adt/gp_optimizer_functions.o \
+	src/backend/utils/adt/interpolate.o \
+	src/backend/utils/adt/json.o \
+	src/backend/utils/adt/jsonfuncs.o \
+	src/backend/utils/adt/like.o \
+	src/backend/utils/adt/like_match.o \
+	src/backend/utils/adt/lockfuncs.o \
+	src/backend/utils/adt/mac.o \
+	src/backend/utils/adt/matrix.o \
+	src/backend/utils/adt/misc.o \
+	src/backend/utils/adt/oracle_compat.o \
+	src/backend/utils/adt/pgstatfuncs.o \
+	src/backend/utils/adt/pivot.o \
+	src/backend/utils/adt/pseudotypes.o \
+	src/backend/utils/adt/quote.o \
+	src/backend/utils/adt/rowtypes.o \
+	src/backend/utils/adt/tsginidx.o \
+	src/backend/utils/adt/tsgistidx.o \
+	src/backend/utils/adt/tsquery.o \
+	src/backend/utils/adt/tsquery_cleanup.o \
+	src/backend/utils/adt/tsquery_gist.o \
+	src/backend/utils/adt/tsquery_op.o \
+	src/backend/utils/adt/tsquery_rewrite.o \
+	src/backend/utils/adt/tsquery_util.o \
+	src/backend/utils/adt/tsrank.o \
+	src/backend/utils/adt/tsvector.o \
+	src/backend/utils/adt/tsvector_op.o \
+	src/backend/utils/adt/tsvector_parser.o \
+	src/backend/utils/adt/txid.o \
+	src/backend/utils/adt/uuid.o \
+	src/backend/utils/adt/xid.o \
+	src/backend/tsearch/dict.o \
+	src/backend/tsearch/dict_ispell.o \
+	src/backend/tsearch/dict_simple.o \
+	src/backend/tsearch/dict_synonym.o \
+	src/backend/tsearch/dict_thesaurus.o \
+	src/backend/tsearch/regis.o \
+	src/backend/tsearch/spell.o \
+	src/backend/tsearch/to_tsany.o \
+	src/backend/tsearch/ts_locale.o \
+	src/backend/tsearch/ts_parse.o \
+	src/backend/tsearch/ts_utils.o \
+	src/backend/tsearch/wparser.o \
+	src/backend/tsearch/wparser_def.o \
 
 # These files are linked into every test program.
 MOCK_OBJS=\
+	$(top_srcdir)/src/test/unit/mock/fmgrtab_mock.o \
+	$(top_srcdir)/src/test/unit/mock/rmgr_mock.o \
 	$(top_srcdir)/src/test/unit/mock/main_mock.o
 # No test programs currently exercise the ORCA translator library, so
 # mock that instead of linking with the real library.

src/test/unit/mock/fmgrtab_mock.c

+/*
+ * This is a mock version of src/backend/utils/fmgrtab.c. The real fmgrtab.c
+ * contains a large table, fmgr_builtins, which contains a pointer to all
+ * the built-in functions that are exposed at SQL-level, in the pg_proc
+ * catalog. We don't need the table in mock tests, and if we leave them out,
+ * we don't need to link in the .o files containing them, which helps to cut
+ * down the size of the test programs.
+ */
+#include "postgres.h"
+
+#include "utils/fmgrtab.h"
+
+const FmgrBuiltin fmgr_builtins[] = { };
+
+const int fmgr_nbuiltins = 0;

src/test/unit/mock/rmgr_mock.c

+/*
+ * This is a mock version of src/backend/access/transam/rmgr.c. The real
+ * rmgr.c contains a table of the WAL redo/desc functions for all the WAL
+ * record types. Leave out the table, so that we can leave out the AM
+ * object files, which helps to cut down the size of the test programs.
+ */
+#include "postgres.h"
+
+#include "access/rmgr.h"
+#include "access/xlog_internal.h"
+
+const RmgrData RmgrTable[RM_MAX_ID + 1];