[clang] [clang][ARM64X] Support compiling both native and EC objects with -marm64x (PR #207612)

[Jacek Caban via cfe-commits]

cjacek wrote:

I changed the objcopy command to use exclude, which uses `IMAGE_SCN_LNK_REMOVE` and should fit better what we need.

https://github.com/llvm/llvm-project/pull/207612