Non-PCH gtest build fails after JDK-8239235 due to a missing include

When building without precompiled headers I get

/priv/d038402/hg/jdk/test/hotspot/gtest/runtime/test_signatureStream.cpp: In member function 'virtual void SignatureStream_check_refcount_test_vm_Test::TestBody()':
/priv/d038402/hg/jdk/test/hotspot/gtest/runtime/test_signatureStream.cpp:37:25: error: variable 'ResourceMark rm' has initializer but incomplete type
   ResourceMark rm(THREAD);