Make checking for 'protected' access in debug info more legible.

Based on code review feedback for r171604 from Chandler Carruth &
Eric Christopher. Enabled by improvements to LLVM made in r171636.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171637 91177308-0d34-0410-b5e6-96231b3b80d8