Fix scope of namespaced DISubprograms when the function definition is out-of-line.
This fixes a regression introduced in r302915.

Using the lexical decl context is not necessary here for what r302915
wast trying to achieve. Not canonicalizing the NamespaceDecl in
getOrCreateNamespace is suficient.

rdar://problem/29339538

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@303222 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 90199139dcd767a3bfc488590a8b27145bce7766)
2 files changed