[gn build] Port 15c49b9

Author: nico

llvm/utils/gn/secondary/clang/unittests/Frontend/BUILD.gn

@@ -10,6 +10,7 @@ unittest("FrontendTests") {
     "//clang/lib/FrontendTool",
     "//clang/lib/Lex",
     "//clang/lib/Sema",
+    "//clang/lib/Tooling",
     "//llvm/lib/Support",
     "//llvm/lib/TargetParser",
   ]
@@ -20,6 +21,7 @@ unittest("FrontendTests") {
     "CompilerInvocationTest.cpp",
     "FixedPointString.cpp",
     "FrontendActionTest.cpp",
+    "NoAlterCodeGenActionTest.cpp",
     "OutputStreamTest.cpp",
     "PCHPreambleTest.cpp",
     "ParsedSourceLocationTest.cpp",