Enable googletest for test utils (facebookincubator#1738)

Summary:
`velox/dwio/dwrf/test/utils/E2EWriterTestUtil.cpp` depends on googletest. Enabling `VELOX_BUILD_TEST_UTILS` now enables googletest.

Pull Request resolved: facebookincubator#1738

Reviewed By: amitkdutta

Differential Revision: D36819015

Pulled By: kgpai

fbshipit-source-id: fbe45a9c893ad78871055de68c8a0a515e3020a4

CMakeLists.txt

@@ -318,7 +318,9 @@ endif()
 # Benchmarks and tests at some places are coupled which is not great. See
 # velox/vector/CMakeLists.txt. TODO: Decouple.
 set(VELOX_DISABLE_GOOGLETEST OFF)
-if(NOT VELOX_BUILD_TESTING AND NOT VELOX_ENABLE_BENCHMARKS_BASIC)
+if(NOT VELOX_BUILD_TEST_UTILS
+   AND NOT VELOX_BUILD_TESTING
+   AND NOT VELOX_ENABLE_BENCHMARKS_BASIC)
   set(VELOX_DISABLE_GOOGLETEST ON)
   add_definitions(-DVELOX_DISABLE_GOOGLETEST)
 endif()