WebDriver: Automation session terminates during navigation process swap

https://bugs.webkit.org/show_bug.cgi?id=245011
rdar://90824741

Reviewed by Devin Rousso and Brent Fulgham.

WebPageProxy::commitProvisionalPage is crashing during some WebDriver sessions due to having a `nullptr` for
`m_provisionalPage` after calling `WebPageProxy::resetStateAfterProcessTermination`. This was occuring because we were
indiscriminately terminating the WebDriver session at that point, but we should not do so when resetting state for a
navigation process swap, as the automation session is very much expected to continue to exist. The reason we end up
without a `m_provisionalPage` is because terminating the automation session cleans up (e.g. closes) the windows under
automation, which in turn is cleaning up the `m_provisionalPage`, since it will no longer exist once the window is gone.

This resolves numerous test crashes in WPT, including encoding/encodeInto.any.serviceworker.html, as well as fixing
issues navigating to `youtube.com` and `twitter.com`.

* Source/WebKit/UIProcess/WebPageProxy.cpp:
(WebKit::WebPageProxy::resetStateAfterProcessTermination):

Canonical link: https://commits.webkit.org/254386@main

Source/WebKit/UIProcess/WebPageProxy.cpp

@@ -8112,15 +8112,16 @@ void WebPageProxy::resetStateAfterProcessTermination(ProcessTerminationReason re
     pageClient().removeAllPDFHUDs();
 #endif
 
-    // For bringup of process swapping, NavigationSwap termination will not go out to clients.
-    // If it does *during* process swapping, and the client triggers a reload, that causes bizarre WebKit re-entry.
-    // FIXME: This might have to change
-    if (reason != ProcessTerminationReason::NavigationSwap)
+    if (reason != ProcessTerminationReason::NavigationSwap) {
+        // For bringup of process swapping, NavigationSwap termination will not go out to clients.
+        // If it does *during* process swapping, and the client triggers a reload, that causes bizarre WebKit re-entry.
+        // FIXME: This might have to change
         navigationState().clearAllNavigations();
 
-    if (m_controlledByAutomation) {
-        if (auto* automationSession = process().processPool().automationSession())
-            automationSession->terminate();
+        if (m_controlledByAutomation) {
+            if (auto* automationSession = process().processPool().automationSession())
+                automationSession->terminate();
+        }
     }
 }