Switch back to sync IInputMethodManager

This logically reverts two recent CLs [1][2] to submit a corresponding
logical revert [3] into frameworks/base to address Bug 190486491.

 [1]: I767069892c713023b064525105ef2b55946b7bb8
      8279b8ee
 [2]: I6733e8b500f5e02d4e14cde4ab7a46f4f716f5d0
      fa01bf30
 [3]: If16ac0de536d9089eb04f6e07b1ee47378124658

Bug: 163453493
Bug: 190486491
Test: make RunSettingsRoboTests ROBOTEST_FILTER="WinscopeTraceTest"
Change-Id: Idea98bd36935a27d886ca337154112e7dd293080
Merged-In: Idea98bd36935a27d886ca337154112e7dd293080