Remove SPHSinglePCQueueEmpty() calls from lfpcqueue_basic_test

lfpcqueue_basic_test is failing for SPHSinglePCQueueEmpty because
lfpcqueue_basic_test uses SPHSinglePCQueueAllocRaw which does not return a
SPHLFEntryHandle_t and so can't call SPHSinglePCQueueEntryComplete and we
never get entryID.detail.valid set and SPHSinglePCQueueEmpty returns false.
So removing SPHSinglePCQueueEmpty() calls from testcase.

	*  src/tests/sphsinglepcqueue_t.c (lfpcqueue_basic_test): Remove
	SPHSinglePCQueueEmpty() calls.