Build libphonenumber-platform for default java version

Due to limitations with jarjar the libphonenumber-platform was built
for java 1.7. Now that it no longer uses jarjar that restriction is no
longer necessary.

Bug: 117818301
Test: make checkbuild
Change-Id: Ic40f84b9cdfd87c5e1bf50d6f4e8729bcc5115e1
1 file changed