Closes PACK-3254
1. Previously, guards were never removed, so a single if statement
containing `if(clearImmediate)` would mean that it's valid in the whole
file to use `clearImmediate` anywhere. Now it's only valid inside the
bodies of conditional. I haven't seen any additional lints caused by
this.
2. `if(process.env.NEXT_RUNTIME === 'edge')` guards are now respected
There are new test cases for each of these.
One new warning from this is the following from
`react/cjs/react.development.js` where the unrelated `typeof` doesn't
silence the error for `new MessageChannel()` anymore
```
function enqueueTask(task) {
if (null === enqueueTaskImpl)
try {
var requireString = ("require" + Math.random()).slice(0, 7);
enqueueTaskImpl = (module && module[requireString]).call(
module,
"timers"
).setImmediate;
} catch (_err) {
enqueueTaskImpl = function (callback) {
!1 === didWarnAboutMessageChannel &&
((didWarnAboutMessageChannel = !0),
"undefined" === typeof MessageChannel &&
console.error(
"This browser does not have a MessageChannel implementation, so enqueuing tasks via await act(async () => ...) will fail. Please file an issue at https://github.com/facebook/react/issues if you encounter this warning."
));
var channel = new MessageChannel(); /// <---------
channel.port1.onmessage = callback;
channel.port2.postMessage(void 0);
};
}
return enqueueTaskImpl(task);
}
```
Niklas Mischkulnig