Stop using deprecated InputMethodSubtype constructor

The constructors of InputMethodSubtype were deprecated in API level 19.
However we cannot yet switch to a new InputMethodSubtypeBuilder style
due to our minimum support API level.

As an intermediate solution, this patch replaces the these API calls
with InputMethodSubtypeCompatUtils.newInputMethodSubtype so that
these legacy API call can be consolidated at the same place.

BUG: 13030512
Change-Id: I561a585f5dbea56c337680b645be5ef07015a0b1