Revert "DebugInfo: Place global constants in their appropriate context."

This reverts commit r205655.

Breaks the compiler-rt build with an assertion failure in LLVM...
reverting while I investigate.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@205664 91177308-0d34-0410-b5e6-96231b3b80d8