Hashlink null comparison

[ncannasse]

When comparing Null<Int> with Int, HL will allocate instead of doing two checks, one for null and one for the integer.

For example:

class Main {

	public var x : Null<Int>;
	
	static function main() {
		var m = new Main();
		var b = m.x == 3;
		trace(b);
	}

}

This produces:

	.10    @1 call 1, Main.new(0)
	.11    @2 field 3,0[6]
	.11    @3 int 4,@7
	.11    @4 todyn 5,4
	.11    @5 jeq 3,5,2

Instead of

	.10    @0 new 0
	.10    @1 call 1, Main.new(0)
	.11    @2 field 3,0[6]
	.11    @3 jnull 3,6
	.11    @5 safecast 4,3
	.11    @6 int 5,@7
	.11    @7 jnoteq 4,5,2

[Simn]

Note that #8426 was never merged, and I don't remember if HL ever fully passed these tests (our conversation there suggests that it didn't).

[yuxiaomao]

Fixed by #11612