[native] Fix Android glog build errors

Summary:
Atul and I noticed an issue compiling glog. It was [this error](google/glog#355 (comment)), and it should've been addressed by `BUILD_TESTING`, but for some reason it wasn't.

I also noticed that the issue would only consistently repro after cleaning all build artifacts. I'm still not sure why that is.

To debug the issue I ran `./gradlew` with the `-i` flag. I saw this in the output:

```
evaluate library symbolize_unittest (armeabi-v7a)
No CMake version was specified in build.gradle. Using default version 3.10.2.
building target executable symbolize_unittest because no targets are specified.
```

This led me to realize that because we weren't specifying `targets`, Gradle was configured to separately build `glog` directly (instead of through our `CMakeLists.txt`), and that was what was causing the issue.

Test Plan:
Make sure Android can build after cleaning all build artifacts:

```
./gradlew clean && rm -rf build && rm -rf app/build && rm -rf app/.cxx && ./gradlew app:installDebug -PreactNativeDevServerPort=8081
```

Reviewers: karol-bisztyga, atul

Reviewed By: atul

Subscribers: KatPo, palys-swm, Adrian

Differential Revision: https://phabricator.ashoat.com/D1231

native/android/app/CMakeLists.txt

@@ -13,7 +13,10 @@ cmake_minimum_required(VERSION 3.4.1)
 set(PACKAGE_NAME "comm_jni_module")
 
 find_package(fbjni REQUIRED CONFIG)
-set(BUILD_TESTING false)
+
+set(BUILD_TESTING OFF)
+set(WITH_GTEST OFF CACHE BOOL "Use googletest" FORCE)
+set(WITH_GFLAGS OFF CACHE BOOL "Use gflags" FORCE)
 add_subdirectory(./build/third-party-ndk/glog/glog-0.5.0/)
 
 include_directories(

native/android/app/build.gradle

@@ -306,6 +306,7 @@ android {
         externalNativeBuild {
             cmake {
                 arguments "-DANDROID_STL=c++_shared"
+                targets "comm_jni_module"
             }
         }
     }