- test_unmap_simple: was assuming that zero buffer was already cleared, which is not guaranteed and resulted in spurious failures

- writesame10_unmap_until_end, writesame16_unmap, writesame16_unmap_until_end were doing an CU_ASSERT *PER-BYTE* in the verification phase,
which was very CPU-intensive. This change uses memcmp on a whole block which finishes much quicker.

test-tool/test_unmap_simple.c

@@ -43,6 +43,7 @@ test_unmap_simple(void)
 	struct unmap_list list[257];
 	unsigned char *buf = alloca(256 * block_size);
 	unsigned char *zbuf = alloca(256 * block_size);
+        memset(zbuf, 0, 256 * block_size);
 
 	logging(LOG_VERBOSE, LOG_BLANK_LINE);
 	logging(LOG_VERBOSE, "Test basic UNMAP");