TPS:sched_get_priority_max failed with SCHED_FIFO policy test

[cocobean]

Test that sched_get_priority_max() returns the maximum value on success for SCHED_FIFO policy.

On open-posix-test 1.5.2:

Ref: conformance/interfaces/sched_get_priority_max/1-2.c

	int result = -1;
	
	result = sched_get_priority_max(SCHED_FIFO);
	
	if(result != -1 && errno == 0 ) {
		printf("The maximum priority for policy SCHED_FIFO is %i.\n",
		       result);
		printf("Test PASSED\n");
		return PTS_PASS;
	} else {
		perror("An error occurs");
		return PTS_FAIL;

Expect Rezult: Test PASSED

Result: An error occurs: Invalid Argument

Tested on: Haiku x86 hrev54807 (FAILED on GCC2 x86, PASSES on GCC8 x86)