* Don't show "context" for classes without either contextType or contextTypes
* For classes with contextTypes, change the label to "legacy context" instead

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Originally reported by @gaearon via https://github.com/bvaughn/react-devtools-experimental/issues/368
case CONTEXT_PROVIDER_SYMBOL_STRING:
            return ElementTypeContext;
          case CONTEXT_CONSUMER_NUMBER:
          case CONTEXT_CONSUMER_SYMBOL_STRING:
            return ElementTypeContext;
          case STRICT_MODE_NUMBER:
          case STRICT_MODE_SYMBOL_STRING:
            return ElementTypeOtherOrUnknown;
          case SUSPENSE_NUMBER:
          case SUSPENSE_SYMBOL_STRING:
          case DEPRECATED_PLACEHOLDER_SYMBOL_STRING:
            return ElementTypeSuspense;
          case PROFILER_NUMBER:
          case PROFILER_SYMBOL_STRING:
            return ElementTypeProfiler;
          default:
            return ElementTypeOtherOrUnknown;
        }
    }
  }
   This is a slightly annoying indirection.
   It is currently necessary because DevTools wants to use unique objects as keys for instances.
   However fibers have two versions.
   We use this set to remember first encountered fiber for each conceptual instance.
  function getPrimaryFiber(fiber: Fiber): Fiber {
    if (primaryFibers.has(fiber)) {
      return fiber;
    }
    const {alternate} = fiber;
    if (alternate != null && primaryFibers.has(alternate)) {