Revert "Introduce script matching for enabling default IME subtypes."

This reverts commit 9e7a1c98.

Seems that that CL causes ArrayIndexOutOfBoundsException when
initializing InputMethodManagerService, which results in an infinite
boot animation.

Bug: 27129703
Bug: 27348943
Change-Id: I474a87876670ac018c675ac7b4608e90fbb2434b