runtime: add MemStats.TotalAlloc

src/runtime/mstats_leaking.go

@@ -9,10 +9,11 @@ package runtime
 // call to ReadMemStats. This would not do GC implicitly for you.
 func ReadMemStats(m *MemStats) {
 	m.HeapIdle = 0
-	m.HeapInuse = uint64(heapptr - heapStart)
+	m.HeapInuse = gcTotalAlloc
 	m.HeapReleased = 0 // always 0, we don't currently release memory back to the OS.
 
 	m.HeapSys = m.HeapInuse + m.HeapIdle
 	m.GCSys = 0
+	m.TotalAlloc = gcTotalAlloc
 	m.Sys = uint64(heapEnd - heapStart)
 }