Revert "Add basic TAP test setup for pg_upgrade"

This reverts commit f41e56c.

The build farm client would run the pg_upgrade tests twice, once as part
of the existing pg_upgrade check run and once as part of picking up all
TAP tests by looking for "t" directories.  Since the pg_upgrade tests
are pretty slow, we will need a better solution or possibly a build farm
client change before we can proceed with this.

Author: petere

src/bin/pg_upgrade/Makefile

@@ -36,9 +36,8 @@ clean distclean maintainer-clean:
 	       pg_upgrade_dump_globals.sql \
 	       pg_upgrade_dump_*.custom pg_upgrade_*.log
 
-check: test.sh
-	$(prove_check)
+check: test.sh all
 	MAKE=$(MAKE) bindir=$(bindir) libdir=$(libdir) EXTRA_REGRESS_OPTS="$(EXTRA_REGRESS_OPTS)" $(SHELL) $< --install
 
-installcheck:
-	$(prove_installcheck)
+# installcheck is not supported because there's no meaningful way to test
+# pg_upgrade against a single already-running server