Migrate to Android Testing Support Lib (part 5/N)

This CL converts 19 test classes under com.android.inputmethod.latin
to Android Testing Support Library.

Bug: 110805255
Test: verified as follows. No new test failures.
        tapas adb LatinIME LatinIMETests arm64 userdebug && \
        DISABLE_PROGUARD=true make -j LatinIME && \
        adb install -r $OUT/system/app/LatinIME/LatinIME.apk && \
        atest LatinIMETests:com.android.inputmethod.latin
Change-Id: I878fcae0126f57c43a644af341e5a0a8ac8f5cc9