Revert create_symbolic_link and both depending changes

This reverts commits r203136, r203137, and r203138.

This code doesn't build on Windows.  Even on Vista+, Windows requires
elevated privileges to create a symlink.  Therefore we can't use
symlinks in the compiler.  We'll have to find another approach.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203143 91177308-0d34-0410-b5e6-96231b3b80d8