swift234

[Tests] Move OS X specific availability printing tests to different file

Move the availability printing tests from IDE/print_clang_decls.swift to
IDE/print_clang_framework.swift (which is only run on OS X). This commit should unbreak
the iOS build bots, which I broke in r24973.

This commit does not address Jordan's concerns with the tests. I will do that in a latter
commit.

Swift SVN r24985