fix(devtools-ios): Ensure UI modifications run on main thread

Modifications to the UI can only be made from the main thread.
Since {N} 5.3.0 all debugger protocol messages are processed
by the worker thread that receives them in iOS.

refs #7219, https://github.com/NativeScript/ios-runtime/pull/1101

tns-core-modules/utils/utils.d.ts

@@ -269,6 +269,26 @@ export function GC();
  */
 export function releaseNativeObject(object: any /*java.lang.Object | NSObject*/);
 
+/**
+ * Dispatches the passed function for execution on the main thread
+ * @param func The function to execute on the main thread.
+ */
+export function executeOnMainThread(func: Function);
+
+/**
+ * Returns a function wrapper which executes the supplied function on the main thread.
+ * The wrapper behaves like the original function and passes all of its arguments BUT
+ * discards its return value.
+ * @param func The function to execute on the main thread
+ * @returns The wrapper function which schedules execution to the main thread
+ */
+export function mainThreadify(func: Function): (...args: any[]) => void
+
+/**
+ * @returns Boolean value indicating whether the current thread is the main thread
+ */
+export function isMainThread(): boolean
+
 /**
  * Returns true if the specified path points to a resource or local file.
  * @param path The path.