Fix concurrency bug in reported file version

[keyboardDrummer]

Fixes #5901 and possibly other failing tests

Description

• For any files open in the editor, record the editor's version number when that file is read, and store this version number throughout compilation so it can be used when emitting notifications for this compilation.

How has this been tested?

• The change in behavior only occurs for a particular race condition, which is difficult to trigger, so I have not added tests.

By submitting this pull request, I confirm that my contribution is made under the terms of the MIT license.

[MikaelMayer]

Looks like this stabilizes the file version number per file instead of per compilation. Hope it works!

[keyboardDrummer]

Looks like this stabilizes the file version number per file instead of per compilation. Hope it works!

Per file per compilation