The "Init Duration" reported by the RIE is wrong

[simonis]

The "Init Duration" reported by the RIE is much too small. It is taken before the actual language runtime is even started:

	initStart, initEnd := InitHandler(sandbox, functionVersion, timeout, bs)

Instead, the end of the Init phase should be recorded when the sendInitRuntimeDoneLogEvent() is posted:

	defer func() {
		sendInitRuntimeDoneLogEvent(execCtx, sbInfoFromInit.SandboxType, runtimeDoneStatus)
	}()