Remove path_tclsh.m4.

Looks like it was only used by dejagnu and is now dead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210022 91177308-0d34-0410-b5e6-96231b3b80d8
[msan] Remove an out-of-date comment.

MSan is no longer an "early prototype".


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210023 91177308-0d34-0410-b5e6-96231b3b80d8