[lld][WebAssembly] Don't allow `--global-base` to be specified in -share/-pie...

[lld][WebAssembly] Don't allow `--global-base` to be specified in -share/-pie or --relocatable modes

Add some checks around this combination of flags

Also, honor `--global-base` when specified in `--stack-first` mode
rather than ignoring it.  But error out if the specified base preseeds
the end of the stack.

Differential Revision: https://reviews.llvm.org/D136117