xref tests occasionally fail

### Description

xref tests occasionally fail due to a race/timing issue.

### Repro steps

`eldev test`

### Expected behavior

All tests pass

### Actual behavior
```
finds definition in pervasives FAILED (347.78ms)
finds definitions in other files of Project (11.74ms)

========================================
F# LSP Client finds definition in pervasives

Traceback (most recent call last):
call-interactively(xref-find-definitions)
funcall-interactively(xref-find-definitions "LSP identifier at point.")
xref-find-definitions("LSP identifier at point.")
xref--find-definitions("LSP identifier at point." nil)
xref--show-defs(#[0 "\212\307\303!\203\303q\210\3101\304b0\202\210\202\210\306\305\302\"\211\204&\311\301\300\"\210\211\262)\207" ["LSP identifier at point." definitions "LSP identifier at point." # 260 eglot xref-backend-definitions buffer-live-p (error) xref--not-found-error] 4] nil)
xref-show-definitions-buffer(#[0 "\212\307\303!\203\303q\210\3101\304b0\202\210\202\210\306\305\302\"\211\204&\311\301\300\"\210\211\262)\207" ["LSP identifier at point." definitions "LSP identifier at point." # 260 eglot xref-backend-definitions buffer-live-p (error) xref--not-found-error] 4] ((window . #) (display-action) (auto-jump)))
error: (wrong-type-argument listp t)

Ran 20 specs, 1 failed, in 16.50s.

```

### Known workarounds

rerun tests

### Related information

All systems in Build matrix