Use try-with-resources and multi-catch exceptions in IMMS.

This CL applies new Java 7 language features try-with-resources
and multi-catch exceptions to InputMethodManagerService.

Basically this is a compile-time replacement hence there should
be neither behavior difference nor performance impact.

Bug: 22285167
Change-Id: I971bd12b63649802859410ee6a91351b1261f055