Migrate to Android Testing Support Lib (part 4/N)

This CL converts 7 test classes under com.android.inputmethod.keyboard
to Android Testing Support Library.

This CL also fix missing annotations in KeyboardLayoutTest.

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.keyboard
Change-Id: I8ab9e3329f159f0df02812fafe44c25efa76c0d1