Fix FastISel dropping srcloc metadata from InlineAsm

Summary:
Bugzilla: https://bugs.llvm.org/show_bug.cgi?id=46060

I've also added the Extra_IsConvergent flag which was missing from FastISel.

Reviewers: echristo

Reviewed By: echristo

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80759