[libclc] Change libclc install dir to ${clang_resource_dir}/lib/libclc in in-tree build (#163896)
Commit df7473673214b placed libclc libraries into clang resource dir
<resource-dir>/lib/libclc at build stage.
This PR does it at install stage as well.
Note that in standalone (not in-tree) build, libclc is still installed
to old ${CMAKE_INSTALL_DATADIR}/clc dir.