Set experimental to false for wasm shared memory

[chrisdavidmills]

As per https://bugzilla.mozilla.org/show_bug.cgi?id=1648685

Looks like this was actually enabled in Firefox 79.

I also put experimental as false, as this is now enabled in multiple browsers (and firefox has its sharedarraybuffer story sorted out for 79)

[Elchi3]

In mdn/sprints#2219 (comment) @annevk said for Firefox 78:

WebAssembly.Memory now supports shared: true in its constructor. (This can be used to get an instance of the SharedArrayBuffer constructor.)

Anne, did that really ship in 78, or is it shipping in 79 now, per https://bugzilla.mozilla.org/show_bug.cgi?id=1648685?

[annevk]

I'm pretty sure that shipped in 78. You can test with new WebAssembly.Memory({ shared:true, initial:0, maximum:0 }).buffer.constructor.

[Elchi3]

Looks like this was actually enabled in Firefox 79.

It was already in 78. Please leave this alone :)

I also put experimental as false, as this is now enabled in multiple browsers (and firefox has its sharedarraybuffer story sorted out for 79)

okay, lets make this change here then, at least.

[chrisdavidmills]

OK, OK, back to 78 it goes ;-)