rutime/gc_leaking: ensure heapptr is aligned on wasm

src/runtime/gc_leaking.go

@@ -53,7 +53,12 @@ func SetFinalizer(obj interface{}, finalizer interface{}) {
 
 func initHeap() {
 	// preinit() may have moved heapStart; reset heapptr
-	heapptr = heapStart
+	ptr := heapStart
+	if GOARCH == "wasm" {
+		// llvm11 and llvm12 do not correctly align the heap on wasm
+		ptr = align(ptr)
+	}
+	heapptr = ptr
 }
 
 // setHeapEnd sets a new (larger) heapEnd pointer.