Migrate hot codepaths to formatSimple().

The recently added TextUtils.formatSimple() can efficiently format
simple strings, roughly 6.5x faster than using String.format().

This change starts using this new method in hot codepaths identified
from pprof traces, and this CL alone should reduce system_process CPU
usage by 0.24%.  Linked bug has detailed pprof screenshots.

Bug: 170978902
Test: atest FrameworksCoreTests:android.text.TextUtilsTest
Exempt-From-Owner-Approval: trivial refactoring
Change-Id: Ie5a21a24be6dfcdb29768fe235e20f050fc111c7