Revert "Switch ztest mmap(2) ASSERTs to VERIFYs"

This reverts commit 2026196.

It is no longer necessary now that we pass -DDEBUG unconditionally.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue openzfs#4095

cmd/ztest/ztest.c

@@ -6185,7 +6185,7 @@ setup_hdr(void)
 
 	hdr = (void *)mmap(0, P2ROUNDUP(sizeof (*hdr), getpagesize()),
 	    PROT_READ | PROT_WRITE, MAP_SHARED, ztest_fd_data, 0);
-	VERIFY3P(hdr, !=, MAP_FAILED);
+	ASSERT(hdr != MAP_FAILED);
 
 	VERIFY3U(0, ==, ftruncate(ztest_fd_data, sizeof (ztest_shared_hdr_t)));
 
@@ -6212,14 +6212,14 @@ setup_data(void)
 
 	hdr = (void *)mmap(0, P2ROUNDUP(sizeof (*hdr), getpagesize()),
 	    PROT_READ, MAP_SHARED, ztest_fd_data, 0);
-	VERIFY3P(hdr, !=, MAP_FAILED);
+	ASSERT(hdr != MAP_FAILED);
 
 	size = shared_data_size(hdr);
 
 	(void) munmap((caddr_t)hdr, P2ROUNDUP(sizeof (*hdr), getpagesize()));
 	hdr = ztest_shared_hdr = (void *)mmap(0, P2ROUNDUP(size, getpagesize()),
 	    PROT_READ | PROT_WRITE, MAP_SHARED, ztest_fd_data, 0);
-	VERIFY3P(hdr, !=, MAP_FAILED);
+	ASSERT(hdr != MAP_FAILED);
 	buf = (uint8_t *)hdr;
 
 	offset = hdr->zh_hdr_size;