Remove NULL check for Self() in TreeTop::join

[tuckermiles70]

OMR::TreeTop::join() checks if self() is NULL [1], which is odd
because it never makes sense to call a member function on a NULL
object. Such calls are undefined behaviour.

Closes: #4835
Signed-off-by: Tucker tuckermiles70@gmail.com

[andrewcraik]

@genie-omr build all

[andrewcraik]

@tuckermiles70 please ensure you have signed the ECA and that you sign your commits - see the contributing guide in the docs directory for details.

[tuckermiles70]

@andrewcraik Sorry about that, should be all good now.

[fjeremic]

@tuckermiles70 thanks for your first contribution. The ECA check has failed again due to the merge commit added to the branch (8bddb1e). The ECA requires that every commit be signed off. The fix is simple. Just squash the entire change into a single commit.

The commit message could be improved slightly [1] to be consistent with the rest of the contributions. Here is a potential example in imperative mood:

Remove NULL check for Self() in TreeTop::join

`OMR::TreeTop::join()` checks if self() is NULL [1], which is odd
because it never makes sense to call a member function on a NULL
object. Such calls are undefined behaviour.

Closes: #4835
Signed-off-by: Tucker <tmiles7@vols.utk.edu>

Once we get that fixed up and all the checks pass I'll kick off a test build and we'll get the change merged. Thanks!

[1] https://github.com/eclipse/omr/blob/master/CONTRIBUTING.md#commit-guidelines

[tuckermiles70]

Thank you @fjeremic and others for being so helpful, I believe I have successfully squashed the commits and strengthened my commit message.

[fjeremic]

@tuckermiles70 we're almost there. There seems to be some foreign commits added to this PR as part of your rebase.

[tuckermiles70]

@fjeremic I believe I have cleared this up

[tuckermiles70]

ECA sign-off status seems to not be getting validated. Making sure my emails are consolidated now

[tuckermiles70]

@fjeremic All checks seem to pass now!

[fjeremic]

@genie-omr build all