Build LLVM on GitHub Action macos-12 host (Xcode 14 + iOS 16 SDK)

Use monospace font in code editor and fix smart quote i.e. automatic …

…replacement of ASCII single/double quote with Unicode quote characters which leads to issue when compiling string literal

Update to LLVM 14.0.0

Update to LLVM 13.0.1

Update to LLVM 12.0

Update documentation now that we build and release LLVM as xcframework

Restore build script for real iOS thank to the issue regarding HAVE_F…

…FI_CALL not detected correctly being fixed as of LLVM 11.0.1 and libffi 5c63b463b87d3c06102a4a7f05f395929d9ea79b

Mention not to expect the JIT-based interpreter to work on real iPhone