[gn build] Port d07c3cf

Author: llvmgnsyncbot

llvm/utils/gn/secondary/llvm/unittests/Support/BUILD.gn

@@ -84,6 +84,7 @@ unittest("SupportTests") {
     "SwapByteOrderTest.cpp",
     "TarWriterTest.cpp",
     "ThreadPool.cpp",
+    "ThreadSafeAllocatorTest.cpp",
     "Threading.cpp",
     "TimeProfilerTest.cpp",
     "TimerTest.cpp",