Fix update validation for L0 and OpenCL

Author: fabiomestre

source/adapters/level_zero/command_buffer.cpp

@@ -1372,7 +1372,7 @@ ur_result_t validateCommandDesc(
   logger::debug("Mutable features supported by device {}", SupportedFeatures);
 
   // Kernel handle updates are not yet supported.
-  if (CommandDesc->hNewKernel != Command->Kernel) {
+  if (CommandDesc->hNewKernel && CommandDesc->hNewKernel != Command->Kernel) {
     return UR_RESULT_ERROR_UNSUPPORTED_FEATURE;
   }
 

source/adapters/opencl/command_buffer.cpp

@@ -547,7 +547,8 @@ UR_APIEXPORT ur_result_t UR_APICALL urCommandBufferUpdateKernelLaunchExp(
         *pUpdateKernelLaunch) {
 
   // Kernel handle updates are not yet supported.
-  if (pUpdateKernelLaunch->hNewKernel != hCommand->Kernel) {
+  if (pUpdateKernelLaunch->hNewKernel &&
+      pUpdateKernelLaunch->hNewKernel != hCommand->Kernel) {
     return UR_RESULT_ERROR_UNSUPPORTED_FEATURE;
   }