ValueMaterializer: rename materializeDeclFor() to materialize()

It may materialize a declaration, or a definition. The name could
be misleading. This is following a merge of materializeInitFor()
into materializeDeclFor().

Differential Revision: http://reviews.llvm.org/D20593

llvm-svn: 270759
GitOrigin-RevId: cc8c107e6a4decedc365a70f4d968c2e064ab2d5
4 files changed