[js] Wrong calculation for Int64 (ushr / add) methods

[flashultra]

The following code return 547226893 ( 0x209E050D ) instead the correct one 4842194189 ( 0x1209E050D )
The problem is only for JS target ( https://try.haxe.org/#212E9Fb4 )

var i:Int64 = Int64.make(0xF0E3FF1B, 0x00000000);
var j:Int64 = Int64.make(0x2FBA05F2, 0x69D9E4DC);
var mcr:Int64 = Int64.ushr(i, 32);
var pcrm:Int64 = Int64.ushr(j, 32);
var result = Int64.add(mcr, pcrm);
trace("Result: " + result);

[flashultra]

Generated JS code :

let i_high = -253493477;
let mcr_low = i_high >>> 0;
let pcrm_low = 800720370 >>> 0;
let low = mcr_low + pcrm_low | 0;

or let low = 4041473819 + 800720370 | 0;

If remove | 0 the result is correct.

[flashultra]

Fixed with #11868