MIPS64: Fix stub_test in a proper way

This reverts commit dc2388f9e7929faecaea9446c6ebd522445ac915 and
fixes stub_test in a proper way. Register names $12-$15 has been
used in the clobber list instead aliases t0-t3 because they are
ambiguous.

Change-Id: Idf8c866267a169c00046cc0a8191ec9712a5f937
1 file changed