Remove arm64 ld.gold workaround (facebook#435)

Summary:
This is no longer necessary, and now causes a build failure.

Pull Request resolved: facebook#435

Test Plan: Build fix verified on CircleCI via Github

Reviewed By: mhorowitz

Differential Revision: D25603599

Pulled By: willholen

fbshipit-source-id: 8df957ceab519382186cead29428bc379e3ac471

CMakeLists.txt

@@ -253,12 +253,6 @@ if (HERMES_IS_ANDROID)
 
   # The release build can focus on size.
   set(CMAKE_CXX_FLAGS_RELEASE "-Os -DNDEBUG")
-
-  if (ANDROID_ABI STREQUAL "arm64-v8a")
-    # Using -flto on arm64 fails due to it using a different linker by default
-    # https://github.com/android-ndk/ndk/issues/242
-    set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -fuse-ld=gold")
-  endif()
 endif()
 
 if(HERMES_BUILD_APPLE_DSYM)