fix: fix getState().testPath during collection with no isolation

[hi-ogawa]

Description

• Closes expect.getState() frequently returns the wrong data when used in the setup file if isolation is not enabled #7638

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[hi-ogawa]

testPath lazily picks up worker state, so overwriting the properly here during onBeforeTryTask makes testPath stale during collection of next tests when no isolation.

vitest/packages/vitest/src/integrations/chai/index.ts

Lines 53 to 55 in b3b8e71

	get testPath() {
	return getWorkerState().filepath
	},