Use fallback to XPC services in Simulator

https://bugs.webkit.org/show_bug.cgi?id=267824
rdar://121324948

Reviewed by Chris Dumez.

There is currently an issue with conflicting bundle IDs in Simulator, between the WebKit extensions,
and the macOS WebKit XPC services. This conflict causes the extension launch path to fail. This can
be resolved by restoring the fallback to the XPC services launch path we had earlier.

* Source/WebKit/Configurations/BaseXPCService.xcconfig:
* Source/WebKit/UIProcess/Launcher/cocoa/ProcessLauncherCocoa.mm:
(WebKit::ProcessLauncher::launchProcess):

Canonical link: https://commits.webkit.org/273269@main

Source/WebKit/Configurations/BaseXPCService.xcconfig

@@ -52,6 +52,7 @@ SKIP_INSTALL[sdk=xr*] = NO;
 SKIP_INSTALL[sdk=appletv*] = NO;
 SKIP_INSTALL[sdk=watch*] = NO;
 SKIP_INSTALL[sdk=macos*] = NO;
+SKIP_INSTALL[sdk=iphonesimulator*] = NO;
 
 WK_ERROR_WHEN_LINKING_WITH_STATIC_INITIALIZERS = -Xlinker -no_inits;
 WK_NO_STATIC_INITIALIZERS = $(WK_NO_STATIC_INITIALIZERS_$(CONFIGURATION)_$(WK_ANY_SANITIZER_ENABLED)_$(ENABLE_LLVM_PROFILE_GENERATION));

Source/WebKit/UIProcess/Launcher/cocoa/ProcessLauncherCocoa.mm

@@ -160,7 +160,7 @@ static void launchWithExtensionKit(ProcessLauncher& processLauncher, ProcessLaun
         if (error) {
             NSLog(@"Error launching process %@ error %@", process, error);
             RELEASE_LOG_FAULT(Process, "Error launching process, description '%s', reason '%s'", String([error localizedDescription]).utf8().data(), String([error localizedFailureReason]).utf8().data());
-#if PLATFORM(IOS)
+#if PLATFORM(IOS) && !PLATFORM(IOS_SIMULATOR)
             // Fallback to legacy extension identifiers
             // FIXME: this fallback is temporary and should be removed when possible. See rdar://120793705.
             callOnMainRunLoop([weakProcessLauncher = weakProcessLauncher] {