fix gradle compliation (#925)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/925

Gradle is failing to compile yoga for two reasons:
1. Ever since `YogaNodeJNIPhantomRefs` was introduced which uses `DestructorThread.Destructor` from fbjni which was the first direct Java dependency from yoga java to fbjni java code.

2. Adding a missing gradle endpoint for `testutil` since it is now required for yoga unit-tests

Reviewed By: SidharthGuglani

Differential Revision: D17274226

fbshipit-source-id: 3df9648321162d34f81fd3675ca1474e8a1c6d3a

testutil/src/main/cpp/CMakeLists.txt

@@ -0,0 +1,30 @@
+#
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+#
+
+cmake_minimum_required(VERSION 3.4.1)
+
+set(CMAKE_VERBOSE_MAKEFILE on)
+
+add_compile_options(
+    -fno-omit-frame-pointer
+    -fexceptions
+    -Wall
+    -std=c++11
+    -DDISABLE_CPUCAP
+    -DDISABLE_XPLAT)
+
+file(GLOB testutil_SRC
+    jni/*.cpp
+    testutil/*.cpp)
+
+add_library(testutil SHARED
+    ${testutil_SRC})
+
+target_include_directories(testutil PRIVATE
+    include)
+
+target_link_libraries(testutil android log)