Revert "Use find_library for ncurses"

The introduction of find_library for ncurses caused more issues than it solved problems. The current open issue is it makes the static build of LLVM fail. It is better to revert for now, and get back to it later.

Revert "[CMake] Fix an issue where get_system_libname creates an empty regex capture on windows"
This reverts commit 1ed1e16a.

Revert "Fix msan build"
This reverts commit 34fe9613.

Revert "[CMake] Always mark terminfo as unavailable on Windows"
This reverts commit 76bf2623.

Revert "[CMake] Fix OCaml build failure because of absolute path in system libs"
This reverts commit 8e4acb82.

Revert "[CMake] Don't look for terminfo libs when LLVM_ENABLE_TERMINFO=OFF"
This reverts commit 495f91fd.

Revert "Use find_library for ncurses"
This reverts commit a52173a3.

Differential revision: https://reviews.llvm.org/D86521