[Android] Add the test case about setDatabaseEnabled

Test database by set the function setDatabaseEnabled true or false. \
Then get the result by load the html which check the database \
enabled or not.

This test case should add the parameter "--test_data", as follows:
build/android/run_instrumentation_tests.py --test-apk XWalkCoreTest \
--test_data xwalkview:xwalk/test/data/device_files/ \
--verbose -I --num_retries=1 -f testDatabaseEnabled