DataLayout: value initialize globals to avoid static construction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195150 91177308-0d34-0410-b5e6-96231b3b80d8
llvm-cov: Added constness property to methods.

Added constness to methods that shouldn't modify objects. Replaced
operator[] lookup in maps with find() instead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195151 91177308-0d34-0410-b5e6-96231b3b80d8
reverts 195057 per request

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195152 91177308-0d34-0410-b5e6-96231b3b80d8