Minimal test IME with Stylus HW support

Minimal IME with Handwriting support that can draw ink trail and commit
random text after each session.

Test: Manually
      1. m -j HandwritingIme
      2. adb install out/../HandwritingIme.apk
      3. Simulate stylus with  I7723be718354872509a9e85beda10acdbe25dd48
      4. and enable the property in #3 with
         adb shell setprop <property> true
      5. Open any app with editor and swipe on EditText.
      6. HW ink window with ink will appear.
Bug: 217957587

Change-Id: I53808ec261bd4364797b93d57cf6a8ddfd615390