Fix perf unit tests somehow (#12088)

Author: morganchen12

FirebasePerformance/Tests/Unit/FPRObjectInstrumentorTest.m

@@ -35,8 +35,6 @@ - (void)testInitWithObject {
   XCTAssertFalse(instrumentor.hasModifications);
 }
 
-#ifdef TODO
-// On Xcode 15, this test fails
 /** Tests copying a selector that's not present on the target object. */
 - (void)testCopySelectorFromClassThatModifies {
   NSObject *object = [[NSObject alloc] init];
@@ -50,11 +48,10 @@ - (void)testCopySelectorFromClassThatModifies {
   XCTAssertTrue([[object class] isSubclassOfClass:[NSObject class]]);
   instrumentor = nil;
   XCTAssertNil(weakInstrumentor);
+  XCTAssertNotNil([(GULSwizzledObject *)object gul_objectSwizzler]);
   XCTAssertNoThrow([(GULSwizzledObject *)object gul_class]);
   XCTAssertEqual([object class], [(GULSwizzledObject *)object gul_class]);
-  XCTAssertNotNil([(GULSwizzledObject *)object gul_objectSwizzler]);
 }
-#endif
 
 /** Tests copying a selector that already exists on the object doesn't work. */
 - (void)testCopySelectorFromClassThatDoesNotModify {