Fix template release build: Add -ObjC and -lc++ to tests target

Summary:
Fixes #11861 - the release config is currently broken for projects created by `react-native init` in `master`, 0.40 and 0.39.

I'm still investigating when and how this got broken but this seems to be a clean fix. I've added `-ObjC` as well to match the main target but I'm not sure yet whether that's necessary.

To test:
```
react-native init fooproject --version react-native@rh389/react-native#missinglinkerflags
```
Open in XCode, Edit scheme (⌘<), Change `Build Configuration` to `Release`, build.

Update: The `-lc++` flag became necessary when 33deaad landed because of the libstdc++ dependencies of `RCTLog`. Still not sure about `-ObjC`. javache ?
Closes #11889

Differential Revision: D4421685

Pulled By: javache

fbshipit-source-id: 954edaef773f8cef7b7ad671fa4d1f2bfc2f20f2

Author: robhogan

local-cli/templates/HelloWorld/ios/HelloWorld.xcodeproj/project.pbxproj

@@ -966,6 +966,10 @@
 				INFOPLIST_FILE = HelloWorldTests/Info.plist;
 				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
+				OTHER_LDFLAGS = (
+					"-ObjC",
+					"-lc++",
+				);
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/HelloWorld.app/HelloWorld";
 			};
@@ -979,6 +983,10 @@
 				INFOPLIST_FILE = HelloWorldTests/Info.plist;
 				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
+				OTHER_LDFLAGS = (
+					"-ObjC",
+					"-lc++",
+				);
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/HelloWorld.app/HelloWorld";
 			};