Rename InputMethodMap#equals() to #areSame()

This is a follow up CL to my previous CL [1], which introduced

  InputMethodMap.equals()

as a static method.

It seems that it would trigger some lint error when it's actually
used. To avoid such an error, just rename it to #areSame().

This is a mechanical renaming. There must be no observable behavior
change.

Bug: 329703038
Test: atest FrameworksInputMethodSystemServerTests:InputMethodInfoUtilsTest
Test: atest FrameworksInputMethodSystemServerTests:InputMethodMapTest
Change-Id: I5f5c7a8a9b250a702fc6d6d1ea41706c04b48ac7