Import patch from mainline GCC to fix an infinite recusion in the Rust demangler.

Import patch from mainline GCC to fix an infinite recusion in the Rust demangler.

	PR 98886
	PR 99935
	* rust-demangle.c (struct rust_demangler): Add a recursion
	counter.
	(demangle_path): Increment/decrement the recursion counter upon
	entry and exit.  Fail if the counter exceeds a fixed limit.
	(demangle_type): Likewise.
	(rust_demangle_callback): Initialise the recursion counter,
	disabling if requested by the option flags.