* 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
const primaryFiber = getPrimaryFiber(fiber);
    if (!fiberToIDMap.has(primaryFiber)) {
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       a
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       t
      primaryFibers.delete(primaryFiber);
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      return;
    }
    const id = getFiberID(primaryFiber);
    if (isRoot) {
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      pendingUnmountedRootID = id;
    } else if (!shouldFilterFiber(fiber)) {
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       w
       a
      if (isSimulated) {
        pendingSimulatedUnmountedIDs.push(id);
      } else {
        pendingRealUnmountedIDs.push(id);
      }
    }
    fiberToIDMap.delete(primaryFiber);
    idToFiberMap.delete(id);
    primaryFibers.delete(primaryFiber);
    const isProfilingSupported = fiber.hasOwnProperty('treeBaseDuration');