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_exec_big.c

@@ -116,7 +116,7 @@ int main(int argc, char **argv)
 
 		for (reloc_ofs = 4096; reloc_ofs < batch_size; reloc_ofs += 4096)
 			if (exec(fd, handle, reloc_ofs))
-				exit(1);
+				igt_fail(1);
 	}
 
 	gem_close(fd, handle);