Verify the locale format within a localeConfig file

Leverage the existing mechanism for validating the locale format to verify whether the locale format of the compiled localeConfig file follows the BCP47 reqular expressions

Bug: 208943132
Test: 1. atest aapt2_tests
      2. Build the app bundle with the local aapt2 in the Android Studio
         a. Make sure the app can be built pass with AGP 7.3.0-alpha06.
	 b. Make sure the app can be built pass by using the local aapt2 with gradle: set the android.aapt2FromMavenOverride=<path> variable in gradle.properties.
	 c. Revove the property above in gradle.properties then apply AGP 7.3.0-alpha07. Make sure the appt2 shows error(AAPT: error: failed to load XML file: No such file or directory) when building the app.
	 d. Add the locale aapt2 with gradle: set the android.aapt2FromMavenOverride=<path> variable in gradle.properties. Make sure the app can be built pass.

Change-Id: Ifa4b9123d36f9c2d450fdf16e1f52963962d7d81