tests: use igt_fail instead of exit(param != 0)

Mostly a sed job with too manual fixups:
- one case of using _exit instead of exit
- and one case which under some conditions use 77, so convert that
  check to an igt_skip.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

tests/gem_tiled_pread_pwrite.c

@@ -142,7 +142,7 @@ main(int argc, char **argv)
 			if (data[j] != j) {
 				fprintf(stderr, "mismatch at %i: %i\n",
 						j, data[j]);
-				exit(1);
+				igt_fail(1);
 			}
 		munmap(data, sizeof(linear));