Move LazyIntToIntMap to services.jar

This class should have lived in services.jar.  When I introduced
LazyIntToIntMap [1] to re-enable cross-profile use of spell checker
APIs, I unnecessarily put this class in frameworks.jar despite the
fact that this utility class is used only in the system server
process.

This CL also makes this utility class package-private so that other
component will not accidentaly depend on it.

This is purely a mechanical refactoring.  There should be no
observable behavior difference.

 [1]: Ic046f832f203115106409a53418a5746eb6d4939
      3f8c5688

Bug: 115516399
Test: atest FrameworksServicesTests:com.android.server.textservices
Change-Id: I9390ba11687e1db66d02fe1cdfb9ed59adde3768