Inconsistent namespace output between tsgo and tsc

[magic-akari]

Input

namespace ns {
  a = 1;
}

namespace ns {
  export declare var a: number;
}

tsc output

"use strict";
var ns;
(function (ns) {
    ns.a = 1;
})(ns || (ns = {}));
(function (ns) {
})(ns || (ns = {}));

tsgo output

var ns;
(function (ns) {
    a = 1;
})(ns || (ns = {}));
(function (ns) {
})(ns || (ns = {}));

context

• export declare sometimes affects JS emit TypeScript#60932

expected behavior

One of the following should happen:

• disallow partial namespace in tsgo
• fix the tsgo output to match the tsc output

[jakebailey]

Dupe of #961

It's going to be the first of your options, since otherwise we can't do concurrent check and emit.