Make Component.waitForReady cooperate with refinding components

[labkey-tchad]

Rationale

A component found with refindWhenNeeded will automatically clear its cache after refinding. This can interfere with elementCache construction.

java.lang.NullPointerException: waitForReady() cleared the element cache
  at java.base/java.util.Objects.requireNonNull(Objects.java:235)
  at org.labkey.test.components.Component.elementCache(Component.java:76)
  at org.labkey.test.components.ui.notifications.ServerNotificationItem.getMessage(ServerNotificationItem.java:83)
  at org.labkey.test.tests.samplemanagement.samples.FMSampleFileImportTest.testCreateStorageWithLabels(FMSampleFileImportTest.java:2592)

If this requireNonNull gets triggered, waitForReady was successful or a component refind was successful. Either way, it should be safe to build a fresh element cache.

Related Pull Requests

• Add more informative errors for null ElementCache #2600

Changes

• Make Component.waitForReady cooperate with refinding components