Remove obsolete filegroup 'api-version-xml'

The last use of the Soong filegroup 'api-version-xml' was removed in
frameworks/base commit 7764a4b84fa. Remove 'api-version-xml'.

Bug: N/A
Test: m checkapi
Change-Id: I2756b77597d1b340aeb860baa0f83a6cfcd7e1fa
1 file changed