[clang] [clang-repl] Fix linking against LLVMLineEditor

LLVMLineEditor library is part of the LLVM dylib.  Move it into
LLVM_LINK_COMPONENTS to avoid duplicate linking when dylib is being
used.  This fixes building standalone clang against installed LLVM
without static libraries.

Differential Revision: https://reviews.llvm.org/D107558