Add a "TypeSpecStartLoc" to FieldDecl. Patch contributed by Enea Zaffanella.

Add a "TypeSpecStartLoc" to FieldDecl. Patch contributed by Enea Zaffanella.

Note: One day, it might be useful to consider adding this info to DeclGroup (as the comments in FunctionDecl/VarDecl suggest). For now, I think this works fine. I considered moving this to ValueDecl (a common ancestor of FunctionDecl/VarDecl/FieldDecl), however this would add overhead to EnumConstantDecl (which would burn memory and isn't necessary).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@75635 91177308-0d34-0410-b5e6-96231b3b80d8