better standard library abort() and panic() implementations for UEFI

[andrewrk]

abort:

zig/std/os/index.zig

Lines 194 to 197 in 2b7e29f

	Os.uefi => {
	// TODO there's gotta be a better thing to do here than loop forever
	while (true) {}
	},

panic:

zig/std/special/panic.zig

Lines 16 to 19 in 2b7e29f

	builtin.Os.uefi => {
	// TODO look into using the debug info and logging helpful messages
	std.os.abort();
	},

[kroepke]

I believe this has been fixed by #2944, maybe close this one?

[fifty-six]

panic was handled in 649b872

and abort was handled in b979fc1