Revert^2 "Default from-text stub generation in build"

This change defaults Java stubs to be generated from API text files
during build. Using the `--build-from-source-stubs` flag, users can
toggle between the feature.

This change relands aosp/2617457.

Test: m nothing && verify ninja path exists between android_stubs_current and android_stubs_current.from-text, and does not exist between android_stubs_current.from-source, m nothing --build-from-source-stub && verify the opposite
Bug: 301522358
Change-Id: Ic129dafc3231e71470af982374739930947b69cb