Docs screenshots tests often fail (due to concurrency?)

[krassowski]

This started to happen more frequently recently. It appears to happen when two tests run concurrently (which depends on the runner assigned my GitHub) in which case both runs tests may create the temporary directory for themselves:

Actual

Expected

Actual

Expected

Notice:   4 failed
    [documentation] › test/documentation/customization.test.ts:190:7 › Customized › should use customized layout 
    [documentation] › test/documentation/general.test.ts:231:7 › General › Open tabs ───────────────
    [documentation] › test/documentation/internationalization.test.ts:14:7 › Internationalization › Menu 
    [documentation] › test/documentation/internationalization.test.ts:43:7 › Internationalization › UI in Chinese 
  4 flaky
    [documentation] › test/documentation/customization.test.ts:14:7 › Default › should use default layout 
    [documentation] › test/documentation/debugger.test.ts:39:7 › Debugger › Activate ───────────────
    [documentation] › test/documentation/debugger.test.ts:124:7 › Debugger › Breakpoints on exception 
    [documentation] › test/documentation/general.test.ts:19:7 › General › Welcome ──────────────────

We should rewrite these snapshot tests to:

• clone demo repo into the test sub-directory or filter out temporary test directories
• maybe not use tree command in terminal but instead something with fixed output