[isolate] Remove unused exception handle

src/contexts.h

Index: src/contexts.h
diff --git a/src/contexts.h b/src/contexts.h
index 14cde4982a3eda2e08b8748c33a2590f54acff17..ad2df2b26bc1395c591ba4bd46125bd7814741f5 100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -80,6 +80,8 @@ enum ContextLookupFlags {
   V(MAP_SET_METHOD_INDEX, JSFunction, map_set)                              \
   V(OBJECT_VALUE_OF, JSFunction, object_value_of)                           \
   V(OBJECT_TO_STRING, JSFunction, object_to_string)                         \
+  V(MICROTASK_RUN_INDEX, JSFunction, microtask_run)                         \
+  V(MICROTASK_ENQ_INDEX, JSFunction, microtask_enq)                         \
   V(PROMISE_CATCH_INDEX, JSFunction, promise_catch)                         \
   V(PROMISE_CHAIN_INDEX, JSFunction, promise_chain)                         \
   V(PROMISE_CREATE_INDEX, JSFunction, promise_create)                       \