[clan-repl] Install clang-repl

[v.g.vassilev]

Summary

This patch installs clang-repl in the install directory.

[v.g.vassilev]

@tstellar, is there a hope to get that in the llvm13 branch?

[teemperor]

This is essentially what D106813 was supposed to do, so this is also LGTM.

You probably want to file a bugreport for @tstellar to cherry-pick this to the release. The biggest impact from this seems to be that it increases the release size and maybe that some maintainers want to package this separately (or not at all). It's probably worth pointing this out when making the cherry-pick bug report.

clang/tools/clang-repl/CMakeLists.txt

   Support
   )
 
-add_clang_executable(clang-repl
+add_clang_tool(clang-repl
   ClangRepl.cpp
   )