Change the "since" arguments generation.

If we add a new sdk library starting with android, there is a build
error because of the wrong "since" argument. So we have to change to
android.txt and android.xml instead of android.* in since-arg.

Bug: 77577799
Test: Verified variable is the same before & after.
Change-Id: I3016181a97e565ebba67c1828d76ddf9a7d6f860