[ReactNative] Avoid method clashing on categories

Summary:
@public

Include `js_name` and `__LINE__` on exported methods' generated names + use the
method implementation instead of `objc_msgSend` on the bridge, so it still works
in case of clashing.

Test Plan: Everything still working, otherwise it'd crash at startup.

React/Base/RCTBridge.m

@@ -496,7 +496,8 @@ static RCTSparseArray *RCTExportedMethodsByModuleID(void)
         Method method = methods[i];
         SEL selector = method_getName(method);
         if ([NSStringFromSelector(selector) hasPrefix:@"__rct_export__"]) {
-          NSArray *entries = ((NSArray *(*)(id, SEL))objc_msgSend)(moduleClass, selector);
+          IMP imp = method_getImplementation(method);
+          NSArray *entries = ((NSArray *(*)(id, SEL))imp)(moduleClass, selector);
           RCTModuleMethod *moduleMethod =
             [[RCTModuleMethod alloc] initWithObjCMethodName:entries[1]
                                                JSMethodName:entries[0]
@@ -1018,7 +1019,7 @@ RCT_INNER_BRIDGE_ONLY(_invokeAndProcessModule:(NSString *)module method:(NSStrin
 
     if ([module conformsToProtocol:@protocol(RCTFrameUpdateObserver)]) {
       [_frameUpdateObservers addObject:module];
-    }
+   }
   }];
 }
 

React/Base/RCTBridgeModule.h

@@ -176,7 +176,7 @@ extern const dispatch_queue_t RCTJSThread;
  * Like RCT_EXTERN_REMAP_METHOD, but allows setting a custom JavaScript name.
  */
 #define RCT_EXTERN_REMAP_METHOD(js_name, method) \
-  + (NSArray *)RCT_CONCAT(__rct_export__, __COUNTER__) { \
+  + (NSArray *)RCT_CONCAT(__rct_export__, RCT_CONCAT(js_name, RCT_CONCAT(__LINE__, __COUNTER__))) { \
     return @[@#js_name, @#method]; \
   } \