fix InstructionBlock when one removes all instructions from an if branch

scripts/Infrastructure/InstructionBlock.py

@@ -98,7 +98,7 @@ class InstructionBlock:
                         result_str += str(op) + "\n"
                     result_str += "}\n"
             else:
-                assert len(val) > 0
+                if len(val) > 0:
                     result_str += "if (rank == %d) {\n" % int(key)
                     for op in val:
                         result_str += str(op) + "\n"