Remove silly unit tests on GUC.

Without assertions, the only thing that was checked was that
numProcsPerSegment() returns 1, when the
gp_resqueue_priority_cpucores_per_segment is 1. That seems excessive, as
numProcsPerSegment() is a trivial function that just returns the value
of gp_resqueue_priority_cpucores_per_segment.

With assertions, it checked that an assertion is thrown if
gp_resqueue_priority_cpucores_per_segment has an invalid value. That seems
excessive, because those assertions are just extra sanity checks. The GUC's
minimum and maximum values prevent it from having invalid values in the
first place.

Linking each mock test program takes a few seconds, so this shaves some
time off the build+unit test process.

src/backend/postmaster/test/Makefile

@@ -2,8 +2,6 @@ subdir=src/backend/postmaster
 top_builddir=../../../..
 include $(top_builddir)/src/Makefile.global
 
-TARGETS=backoff syslogger
+TARGETS=syslogger
 
 include $(top_builddir)/src/backend/mock.mk
-
-backoff.t: $(MOCK_DIR)/backend/utils/error/assert_mock.o

src/backend/postmaster/test/backoff_test.c

-#include <stdarg.h>
-#include <stddef.h>
-#include <setjmp.h>
-#include "cmockery.h"
-
-#include "c.h"
-#include "../backoff.c"
-#include "postgres.h"
-
-#ifdef USE_ASSERT_CHECKING
-/* Function passed to the testing framework in order to catch
- * the failed assertion.
- */
-void
-_ExceptionalCondition( )
-{
-	PG_RE_THROW();
-}
-
-/* Calls _ExceptionalCondition after ExceptionalCondition is
- executed. */
-void
-_AssertionSetting()
-{
-	expect_any(ExceptionalCondition,conditionName);
-	expect_any(ExceptionalCondition,errorType);
-	expect_any(ExceptionalCondition,fileName);
-	expect_any(ExceptionalCondition,lineNumber);
-	will_be_called_with_sideeffect(ExceptionalCondition,&_ExceptionalCondition,NULL);
-}
-#endif
-
-/* Tests that calling numProcsPerSegment doesn't change the value of gp_resqueue_priority_cpucores_per_segment. */
-void
-test__numProcsPerSegment__VerifyImmutableAssignment(void **state)
-{
-	gp_resqueue_priority_cpucores_per_segment = 1;
-	gp_enable_resqueue_priority = 1;
-
-	/* backoffSingleton is required to be non-null for successful execution of numProcsPerSegment. */
-	backoffSingleton = 1;
-	
-	build_guc_variables();
-
-	assert_true(numProcsPerSegment() == 1);
-}
-
-#ifdef USE_ASSERT_CHECKING
-/* Tests assigning gp_resqueue_priority_cpucores_per_segment a negative
- * number. */
-void
-test__numProcsPerSegment__NotNegative(void **state)
-{
-	gp_enable_resqueue_priority = 1;
-	backoffSingleton = 1;
-	gp_resqueue_priority_cpucores_per_segment = -1;
-
-	build_guc_variables();
-
-	_AssertionSetting();
-
-	/* Catch Mocked Assertion */
-	PG_TRY();
-	{
-		numProcsPerSegment();
-	}
-	PG_CATCH();
-	{
-		return;
-	}
-	PG_END_TRY();
-	assert_true(false);
-}
-#endif
-
-#ifdef USE_ASSERT_CHECKING
-/* Tests assigning gp_resqueue_priority_cpucores_per_segment = 0; */
-void
-test__numProcsPerSegment__NotZero(void **state)
-{
-	gp_enable_resqueue_priority = 1;
-	backoffSingleton = 1;
-	gp_resqueue_priority_cpucores_per_segment = 0;
-
-	build_guc_variables();
-
-	_AssertionSetting();
-
-	/* Catch Mocked Assertion */
-	PG_TRY();
-	{
-		numProcsPerSegment();
-	}
-	PG_CATCH();
-	{
-		return;
-	}
-	PG_END_TRY();
-
-	assert_true(false);
-	
-}
-#endif
-
-int
-main(int argc, char* argv[]) {
-        cmockery_parse_arguments(argc, argv);
-
-        const UnitTest tests[] = {
-        		unit_test(test__numProcsPerSegment__VerifyImmutableAssignment)
-#ifdef USE_ASSERT_CHECKING			
-			, unit_test(test__numProcsPerSegment__NotNegative)
-                        , unit_test(test__numProcsPerSegment__NotZero)
-#endif  
-	};
-        return run_tests(tests);
-}
-
-