[Builtin] Implement lit-test support

Summary:
This patch implements a initial support of lit test for builtins.
Unit/arm/call_apsr.S is updated to support thumb1.
It also fixes a bug in arm/aeabi_uldivmod_test.c
gcc_personality_test is XFAILED as the framework cannot handle it so far.
cpu_model_test is also XFAILED for now as it is expected to return non-zero.

Reviewers: rengolin, compnerd, jroelofs, erik.pilkington, arphaman

Reviewed By: jroelofs

Subscribers: jroelofs, aemerson, srhines, nemanjai, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D30802

llvm-svn: 297566