Revert "[Tooling] [0/1] Refactor FrontendActionFactory::create() to return std::unique_ptr<>"

This reverts commit rL326201

This broke gcc4.8 builds, compiler just segfaults:¬
http://lab.llvm.org:8011/builders/clang-atom-d525-fedora-rel/builds/14909¬
http://lab.llvm.org:8011/builders/clang-x86_64-linux-abi-test/builds/22673¬

llvm-svn: 326204
diff --git a/clang/unittests/Tooling/TestVisitor.h b/clang/unittests/Tooling/TestVisitor.h
index acaaabf..fb6a76c 100644
--- a/clang/unittests/Tooling/TestVisitor.h
+++ b/clang/unittests/Tooling/TestVisitor.h
@@ -82,8 +82,8 @@
   }
 
 protected:
-  virtual std::unique_ptr<FrontendAction> CreateTestAction() {
-    return llvm::make_unique<TestAction>(this);
+  virtual ASTFrontendAction* CreateTestAction() {
+    return new TestAction(this);
   }
 
   class FindConsumer : public ASTConsumer {