test_rdwr_fallback
void test_rdwr_fallback(int, bool, bool);
DEF(rdwr_fallback_RDONLY) { test_rdwr_fallback(O_RDONLY, false, true); }
DEF(rdwr_fallback_WRONLY) { test_rdwr_fallback(O_WRONLY, true, false); }
test_rdwr_fallback(O_RDWR, true, expread);