[DebugInfo] Make sure all DBG_VALUEs' reguse operands have IsDebug property

Summary:
In some cases, these operands lacked the IsDebug property, which is meant to signal that
they should not affect codegen. This patch adds a check for this property in the
MachineVerifier and adds it where it was missing.

This includes refactorings to use MachineInstrBuilder construction functions instead of
manually setting up the intrinsic everywhere.

Patch by: JesperAntonsson

Reviewers: aprantl, rnk, echristo, javed.absar

Reviewed By: aprantl

Subscribers: qcolombet, sdardis, nemanjai, JDevlieghere, atanasyan, llvm-commits

Differential Revision: https://reviews.llvm.org/D48319

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335214 91177308-0d34-0410-b5e6-96231b3b80d8
16 files changed