StandaloneMmPkg: Assert if dispatcher fails memory allocation

If the Dispatcher fails to allocate memory for the driver that it is
trying to load then ASSERT, else the Dispatcher silently stops loading
subsequent drivers from the FV.

Signed-off-by: Girish Mahadevan <gmahadevan@nvidia.com>
Reviewed-by: Jeff Brasen <jbrasen@nvidia.com>

StandaloneMmPkg/Core/Dispatcher.c

@@ -144,6 +144,7 @@ MmLoadImage (
              &DstBuffer
              );
   if (EFI_ERROR (Status)) {
+    ASSERT_EFI_ERROR (Status);
     return Status;
   }