Refactor RCTUnsafeExecute{On,Once}MainQueueSync utils

Summary:
Just refactoring the control flow in these functions (in a separate diff). So, that the logic in subsequent diffs is easier to read: D74769326.

Note: I made the second argument to RCTUnsafeExecuteOnMainQueueSyncWithError nullable.

Changelog: [Internal]

Differential Revision: D74940681

Author: RSNara

packages/react-native/React/Base/RCTUtils.h

@@ -49,7 +49,7 @@ RCT_EXTERN void RCTExecuteOnMainQueue(dispatch_block_t block);
 // Legacy function to execute the specified block on the main queue synchronously.
 // Please do not use this unless you know what you're doing.
 RCT_EXTERN void RCTUnsafeExecuteOnMainQueueSync(dispatch_block_t block);
-RCT_EXTERN void RCTUnsafeExecuteOnMainQueueSyncWithError(dispatch_block_t block, NSString *context);
+RCT_EXTERN void RCTUnsafeExecuteOnMainQueueSyncWithError(dispatch_block_t block, NSString *_Nullable context);
 
 // Get screen metrics in a thread-safe way
 RCT_EXTERN CGFloat RCTScreenScale(void);

packages/react-native/React/Base/RCTUtils.mm

@@ -299,52 +299,52 @@ void RCTExecuteOnMainQueue(dispatch_block_t block)
 // unless you know what you are doing.
 void RCTUnsafeExecuteOnMainQueueSync(dispatch_block_t block)
 {
-  if (RCTIsMainQueue()) {
-    block();
-  } else {
-    if (facebook::react::ReactNativeFeatureFlags::disableMainQueueSyncDispatchIOS()) {
-      RCTLogError(@"RCTUnsafeExecuteOnMainQueueSync: Sync dispatches to the main queue can deadlock React Native.");
-    }
-    dispatch_sync(dispatch_get_main_queue(), ^{
-      block();
-    });
-  }
+  RCTUnsafeExecuteOnMainQueueSyncWithError(block, nil);
 }
 
 // Please do not use this method
 // unless you know what you are doing.
-void RCTUnsafeExecuteOnMainQueueSyncWithError(dispatch_block_t block, NSString *context)
+void RCTUnsafeExecuteOnMainQueueSyncWithError(dispatch_block_t block, NSString *_Nullable context)
 {
   if (RCTIsMainQueue()) {
     block();
-  } else {
-    if (facebook::react::ReactNativeFeatureFlags::disableMainQueueSyncDispatchIOS()) {
-      RCTLogError(@"RCTUnsafeExecuteOnMainQueueSync: %@", context);
-    }
-    dispatch_sync(dispatch_get_main_queue(), ^{
-      block();
-    });
+    return;
   }
+
+  if (facebook::react::ReactNativeFeatureFlags::disableMainQueueSyncDispatchIOS()) {
+    RCTLogError(
+        @"RCTUnsafeExecuteOnMainQueueSync: %@",
+        context ?: @"Sync dispatches to the main queue can deadlock React Native.");
+  }
+
+  dispatch_sync(dispatch_get_main_queue(), ^{
+    block();
+  });
 }
 
 static void RCTUnsafeExecuteOnMainQueueOnceSync(dispatch_once_t *onceToken, dispatch_block_t block)
 {
   // The solution was borrowed from a post by Sophie Alpert:
   // https://sophiebits.com/2014/04/02/dispatch-once-initialization-on-the-main-thread
   // See also: https://www.mikeash.com/pyblog/friday-qa-2014-06-06-secrets-of-dispatch_once.html
-  if (RCTIsMainQueue()) {
+  auto executeOnce = ^{
     dispatch_once(onceToken, block);
-  } else {
-    if (DISPATCH_EXPECT(*onceToken == 0L, NO)) {
-      if (facebook::react::ReactNativeFeatureFlags::disableMainQueueSyncDispatchIOS()) {
-        RCTLogError(
-            @"RCTUnsafeExecuteOnMainQueueOnceSync: Sync dispatches to the main queue can deadlock React Native.");
-      }
-      dispatch_sync(dispatch_get_main_queue(), ^{
-        dispatch_once(onceToken, block);
-      });
-    }
+  };
+
+  if (RCTIsMainQueue()) {
+    executeOnce();
+    return;
+  }
+
+  if (!DISPATCH_EXPECT(*onceToken == 0L, NO)) {
+    return;
+  }
+
+  if (facebook::react::ReactNativeFeatureFlags::disableMainQueueSyncDispatchIOS()) {
+    RCTLogError(@"RCTUnsafeExecuteOnMainQueueOnceSync: Sync dispatches to the main queue can deadlock React Native.");
   }
+
+  dispatch_sync(dispatch_get_main_queue(), executeOnce);
 }
 
 CGFloat RCTScreenScale(void)