Introduce FunctionDecl::getLatestDeclaration() and VarDecl::getLatestDeclaration().

For multiple redeclarations they return the last one.

Also, add some non const versions of methods.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@75603 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed