Stop flowing and then abort if a stream is cancelled (#27405)

We currently abort a stream either it's explicitly told to abort (e.g.
by an abortsignal). In this case we still finish writing what we have as
well as instructions for the client about what happened so it can
trigger fallback cases and log appropriately.

We also abort a request if the stream itself cancels. E.g. if you can't
write anymore. In this case we should not write anything to the outgoing
stream since it's supposed to be closed already now. However, we should
still abort the request so that more work isn't performed and so that we
can log the reason for it to the onError callback.

We should also not do any work after aborting.

There we need to stop the "flow" of bytes - so I call stopFlowing in the
cancel case before aborting.

The tests were testing this case but we had changed the implementation
to only start flowing at initial read (pull) instead of start like we
used to. As a result, it was no longer covering this case. We have to
call reader.read() in the tests to start the flow so that we need to
cancel it.

We also were missing a final assertion on the error logs and since we
were tracking them explicitly the extra error was silenced.

DiffTrain build for [d9e00f7](d9e00f7)

compiled/facebook-www/REVISION

@@ -1 +1 @@
-68ac6dbcf8d58a67e94e9061395dd96a52d92377
+d9e00f795b77676fb14f2a3c6f421f48f73bec2a

compiled/facebook-www/ReactDOMServer-dev.classic.js

@@ -19,7 +19,7 @@ if (__DEV__) {
 var React = require("react");
 var ReactDOM = require("react-dom");
 
-var ReactVersion = "18.3.0-www-classic-24cad190";
+var ReactVersion = "18.3.0-www-classic-8314963c";
 
 // This refers to a WWW module.
 var warningWWW = require("warning");
@@ -13120,7 +13120,7 @@ function startFlowing(request, destination) {
     logRecoverableError(request, error);
     fatalError(request, error);
   }
-} // This is called to early terminate a request. It puts all pending boundaries in client rendered state.
+}
 
 function abort(request, reason) {
   try {

compiled/facebook-www/ReactDOMServer-dev.modern.js

@@ -19,7 +19,7 @@ if (__DEV__) {
 var React = require("react");
 var ReactDOM = require("react-dom");
 
-var ReactVersion = "18.3.0-www-modern-0d8cdce2";
+var ReactVersion = "18.3.0-www-modern-4ddb3d62";
 
 // This refers to a WWW module.
 var warningWWW = require("warning");
@@ -12868,7 +12868,7 @@ function startFlowing(request, destination) {
     logRecoverableError(request, error);
     fatalError(request, error);
   }
-} // This is called to early terminate a request. It puts all pending boundaries in client rendered state.
+}
 
 function abort(request, reason) {
   try {

compiled/facebook-www/ReactDOMServerStreaming-dev.modern.js

@@ -12738,7 +12738,7 @@ function startFlowing(request, destination) {
     logRecoverableError(request, error);
     fatalError(request, error);
   }
-} // This is called to early terminate a request. It puts all pending boundaries in client rendered state.
+}
 
 function abort(request, reason) {
   try {

compiled/facebook-www/ReactTestRenderer-dev.modern.js

@@ -24360,7 +24360,7 @@ function createFiberRoot(
   return root;
 }
 
-var ReactVersion = "18.3.0-www-modern-959bcb71";
+var ReactVersion = "18.3.0-www-modern-9ffb854c";
 
 // Might add PROFILE later.