Make prerendering always non-blocking with fix (#31452)

We've previously failed to land this change due to some internal apps
seeing infinite render loops due to external store state updates during
render. It turns out that since the `renderWasConcurrent` var was moved
into the do block, the sync render triggered from the external store
check was stuck with a `RootSuspended` `exitStatus`. So this is not
unique to sibling prerendering but more generally related to how we
handle update to a sync external store during render.

We've tested this build against local repros which now render without
crashes. We will try to add a unit test to cover the scenario as well.

---------

Co-authored-by: Andrew Clark <git@andrewclark.io>
Co-authored-by: Rick Hanlon <rickhanlonii@fb.com>

DiffTrain build for [989af12](989af12)

Author: jackpope

compiled/facebook-www/REVISION

@@ -1 +1 @@
-682a103cde99a3091850d1c27de8846b5d14e803
+989af12f72080c17db03ead91d99b6394a215564

compiled/facebook-www/REVISION_TRANSFORMS

@@ -1 +1 @@
-682a103cde99a3091850d1c27de8846b5d14e803
+989af12f72080c17db03ead91d99b6394a215564

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

@@ -1819,7 +1819,7 @@ __DEV__ &&
     exports.useTransition = function () {
       return resolveDispatcher().useTransition();
     };
-    exports.version = "19.0.0-www-classic-682a103c-20241107";
+    exports.version = "19.0.0-www-classic-989af12f-20241108";
     "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
       "function" ===
         typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

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

@@ -1819,7 +1819,7 @@ __DEV__ &&
     exports.useTransition = function () {
       return resolveDispatcher().useTransition();
     };
-    exports.version = "19.0.0-www-modern-682a103c-20241107";
+    exports.version = "19.0.0-www-modern-989af12f-20241108";
     "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
       "function" ===
         typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

compiled/facebook-www/React-prod.classic.js

@@ -619,4 +619,4 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.0.0-www-classic-682a103c-20241107";
+exports.version = "19.0.0-www-classic-989af12f-20241108";

compiled/facebook-www/React-prod.modern.js

@@ -619,4 +619,4 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.0.0-www-modern-682a103c-20241107";
+exports.version = "19.0.0-www-modern-989af12f-20241108";

compiled/facebook-www/React-profiling.classic.js

@@ -623,7 +623,7 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.0.0-www-classic-682a103c-20241107";
+exports.version = "19.0.0-www-classic-989af12f-20241108";
 "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
   "function" ===
     typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

compiled/facebook-www/React-profiling.modern.js

@@ -623,7 +623,7 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.0.0-www-modern-682a103c-20241107";
+exports.version = "19.0.0-www-modern-989af12f-20241108";
 "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
   "function" ===
     typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&