Update xTaskGetIdleTaskHandle() For SMP (#868)

* Update xTaskGetIdleTaskHandle() in SMP

This commit updates xTaskGetIdleTaskHandle() for SMP in the following ways:

- xTaskGetIdleTaskHandle() no longer accepts xCoreID argument in SMP so that
there is not change in API between single-core and SMP
- xTaskGetIdleTaskHandle() now returns the Active idle task handle in SMP,
which matches the behavior in single-core.
- Added xTaskGetIdleTaskHandleForCore() in SMP which accepts an xCoreID
argument. This function can be used to obtain the Passive idle task handles.

* Update xTaskGetIdleTaskHandle

---------

Co-authored-by: Ching-Hsin Lee <chinglee@amazon.com>
Co-authored-by: chinglee-iot <61685396+chinglee-iot@users.noreply.github.com>
Co-authored-by: Rahul Kar <118818625+kar-rahul-aws@users.noreply.github.com>
Co-authored-by: Gaurav-Aggarwal-AWS <33462878+aggarg@users.noreply.github.com>

include/FreeRTOS.h

@@ -1886,14 +1886,20 @@
     #ifndef traceENTER_xTaskGetIdleTaskHandle
         #define traceENTER_xTaskGetIdleTaskHandle()
     #endif
-#else
-    #ifndef traceENTER_xTaskGetIdleTaskHandle
-        #define traceENTER_xTaskGetIdleTaskHandle( xCoreID )
+#endif
+
+#if ( configNUMBER_OF_CORES == 1 )
+    #ifndef traceRETURN_xTaskGetIdleTaskHandle
+        #define traceRETURN_xTaskGetIdleTaskHandle( xIdleTaskHandle )
     #endif
 #endif
 
-#ifndef traceRETURN_xTaskGetIdleTaskHandle
-    #define traceRETURN_xTaskGetIdleTaskHandle( xIdleTaskHandle )
+#ifndef traceENTER_xTaskGetIdleTaskHandleForCore
+    #define traceENTER_xTaskGetIdleTaskHandleForCore( xCoreID )
+#endif
+
+#ifndef traceRETURN_xTaskGetIdleTaskHandleForCore
+    #define traceRETURN_xTaskGetIdleTaskHandleForCore( xIdleTaskHandle )
 #endif
 
 #ifndef traceENTER_vTaskStepTick