fix: test.each() in vitest differs from jest

[jfparadis-appomni]

• Fixes test.each() in vitest differs from jest #2278

Previously:

• every test case was tested individually to see if it's an array,
• if so, the test case was spread as test parameters (in the test callback function).

This PR makes test.each() follow the same algorithm as jest-each:

• the array of test cases is first evaluated to see it's a table (an array of arrays),
• if so, then all test cases are spread as test parameters, otherwise not.

This means for example that a single array in a series of test cases is not spread as test parameters.

Note that Jest pre-normalize the table, which we can still can avoid here, and process each row on the fly.
https://github.com/facebook/jest/blob/main/packages/jest-each/src/table/array.ts#L49

[sheremet-va]

We already have an open PR #2064

[antfu]

Thank you for working on this! Close in favor of #2064