[COFF, ARM64] Implement Intrinsic.sponentry for AArch64

Summary: This patch adds Intrinsic.sponentry. This intrinsic is required to correctly support setjmp for AArch64 Windows platform.

Reviewers: mgrang, TomTan, rnk, compnerd, mstorsjo, efriedma

Reviewed By: efriedma

Subscribers: majnemer, chrib, javed.absar, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D53673

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345791 91177308-0d34-0410-b5e6-96231b3b80d8
10 files changed