[GISel]: Add MachineIRBuilder support for passing in Flags while building

https://reviews.llvm.org/D55516

Add the ability to pass in flags to buildInstr calls. Currently no
validation is performed but that can be easily performed based on the
opcode (if necessary).

Reviewed by: paquette.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348893 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed