[clang] Fix bazel after eccc6e2. (#152681)

Author: bartchr808

utils/bazel/llvm-project-overlay/clang/unittests/BUILD.bazel

@@ -688,6 +688,7 @@ cc_test(
         "//clang:ast",
         "//clang:basic",
         "//clang:codegen",
+        "//clang:config",
         "//clang:frontend",
         "//clang:interpreter",
         "//clang:lex",