DiffEditor cannot be closed using close()

[lszomoru]

Does this issue occur when all extensions are disabled?: Yes/No

• VS Code Version:
• OS Version:

Steps to Reproduce:

1. Create a new extension that uses the tabs proposed api
2. Open couple of files, and couple of diff editors
3. Create a command that executes await window.tabs[0].close();

Expected: Invoking the command would close each tab one by one
Actual: Tabs contains files get closed, but diff editors do not

[lramos15]

I was trying to support non text diffs which was messing up matches. @mattbierner or @bpasero Do you know if we have any example of non text diffs that I can use for testing?

[bpasero]

Compare 2 notebooks?

[bpasero]

Or 2 binary files / images.