Remove CallContext.of()

[HonahX]

This PR is a follow-up of #1806 to remove all usage of CallContext.of() in tests and the method itself

[HonahX]

Do we want to go through a deprecation process for this even though it is a test only thing?

[flyrain]

I don't think we have to do that. We can follow the process after 1.0.

[dimas-b]

Changes LGTM overall, but I have a question about the rationale for some of them (as commented below)

[dimas-b]

How is it related to the removal of CallContext.of()?

[HonahX]

This helps remove the CallContext.of() in BasePolarisMetaStoreManagerTest, where some tests have the following pattern

@Test
  protected void testCreateEntitiesAlreadyExisting() {
    PolarisMetaStoreManager metaStoreManager = polarisTestMetaStoreManager.polarisMetaStoreManager;
    CallContext callCtx =
        CallContext.of(() -> "testRealm", polarisTestMetaStoreManager.polarisCallContext);
    if (CallContext.getCurrentContext() == null) {
      CallContext.setCurrentContext(callCtx);
    }

The polarisTestMetaStoreManager above is initialized in PolarisEclipseLinkMetaStoreManagerTest (and other persistence specific test class)

BTW, this change will disappear anyway with Yun's #1813 : )

[dimas-b]

Yes, #1813 appears to introduce this change in a more logically consistent way. Let's merge it first :)