libandroidfw_tests: package test data correctly

- Convert to use soong, which allows bundling test data with benchmarks.
- Also separate libandroidfw_benchmarks so that it doesn't depend
on gtest.

Test: manual
Change-Id: I45bd222fafa87172c77b7f5bb2a7a89ddca72361
diff --git a/libs/androidfw/tests/BenchMain.cpp b/libs/androidfw/tests/BenchMain.cpp
index 105c5f9..58fc54a 100644
--- a/libs/androidfw/tests/BenchMain.cpp
+++ b/libs/androidfw/tests/BenchMain.cpp
@@ -18,7 +18,7 @@
 
 #include "benchmark/benchmark.h"
 
-#include "TestHelpers.h"
+#include "BenchmarkHelpers.h"
 
 int main(int argc, char** argv) {
   ::benchmark::Initialize(&argc, argv);