Created a unified Android test for coverage.

[ Merge of http://go/wvgerrit/143889 ]

New test binary for generating code coverage information.  Run several
reliable, short runnning unit tests.  Actual test failures do not
affect the result of this test.

Bug: 138941105
Bug: 191681397
Test: Android cdm_coverage_test
Change-Id: I6b74d361a8a0e2896e0489acaa64d264158ecaa4

libwvdrmengine/cdm/test/unit-test.mk

@@ -22,7 +22,6 @@ LOCAL_SRC_FILES := \
     ../core/test/url_request.cpp \
     ../../oemcrypto/test/oec_device_features.cpp \
     ../util/test/test_sleep.cpp \
-    ./cdm_test_main.cpp \
 
 LOCAL_C_INCLUDES := \
     vendor/widevine/libwvdrmengine/android/cdm/test \
@@ -47,6 +46,7 @@ LOCAL_STATIC_LIBRARIES := \
     libjsmn \
     libgmock \
     libgtest \
+    libgtest_main \
     libwvlevel3 \
 
 LOCAL_SHARED_LIBRARIES := \