[CodeGen] Rename DEBUG_TYPE for default hazard recognizer.

Summary:
The DEBUG_TYPE of the default hazard recognizer should be updated to
match the DEBUG_TYPE of the machine-scheduler pass.

Reviewers: rampitec

Reviewed By: rampitec

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61359

llvm-svn: 360198