runtime: remove minSched hack for wasm

I am not entirely sure what it's doing (it seems related to js.FuncOf),
but tests still seem to pass when this code is removed. So let's remove
it.

src/runtime/runtime_wasm_js.go

@@ -4,13 +4,6 @@ package runtime
 
 type timeUnit float64 // time in milliseconds, just like Date.now() in JavaScript
 
-// wasmNested is used to detect scheduler nesting (WASM calls into JS calls back into WASM).
-// When this happens, we need to use a reduced version of the scheduler.
-//
-// TODO: this variable can probably be removed once //go:wasmexport is the only
-// allowed way to export a wasm function (currently, //export also works).
-var wasmNested bool
-
 var handleEvent func()
 
 //go:linkname setEventHandler syscall/js.setEventHandler

src/runtime/runtime_wasm_js_scheduler.go

@@ -8,24 +8,10 @@ func resume() {
 		handleEvent()
 	}()
 
-	if wasmNested {
-		minSched()
-		return
-	}
-
-	wasmNested = true
 	scheduler(false)
-	wasmNested = false
 }
 
 //export go_scheduler
 func go_scheduler() {
-	if wasmNested {
-		minSched()
-		return
-	}
-
-	wasmNested = true
 	scheduler(false)
-	wasmNested = false
 }

src/runtime/scheduler.go

@@ -247,24 +247,6 @@ func scheduler(returnAtDeadlock bool) {
 	}
 }
 
-// This horrible hack exists to make WASM work properly.
-// When a WASM program calls into JS which calls back into WASM, the event with which we called back in needs to be handled before returning.
-// Thus there are two copies of the scheduler running at once.
-// This is a reduced version of the scheduler which does not deal with the timer queue (that is a problem for the outer scheduler).
-func minSched() {
-	scheduleLog("start nested scheduler")
-	for !schedulerDone {
-		t := runqueue.Pop()
-		if t == nil {
-			break
-		}
-
-		scheduleLogTask("  run:", t)
-		t.Resume()
-	}
-	scheduleLog("stop nested scheduler")
-}
-
 func Gosched() {
 	runqueue.Push(task.Current())
 	task.Pause()