[gn build] Port 6128ff6

Author: llvmgnsyncbot

llvm/utils/gn/secondary/llvm/unittests/ExecutionEngine/JITLink/BUILD.gn

@@ -17,8 +17,9 @@ unittest("JITLinkTests") {
     "AArch32ErrorTests.cpp",
     "AArch32Tests.cpp",
     "EHFrameSupportTests.cpp",
-    "JITLinkMocks.cpp",
+    "JITLinkTestUtils.cpp",
     "LinkGraphTests.cpp",
+    "MachOLinkGraphTests.cpp",
     "MemoryManagerErrorTests.cpp",
     "StubsTests.cpp",
   ]