Change the check-formatting script in CI to format everything in test, not just test/src

[eric-hughes-tiledb]

Change the check-formatting script in CI to format everything in test, not just test/src. We're using that directory more extensively than in the past.

---

TYPE: NO_HISTORY
DESC: Change the check-formatting script in CI to format everything in test, not just test/src

[eric-hughes-tiledb]

The format test is failing in test/external/src/absl_link_test.cc, introduced in #3454 last Friday. There's a large block comment that's clang-format is mangling. @dhoke4tdb, since that's your code, would you reformat that in a way compatible with clang-format and push to the branch for this PR?

[ihnorton]

Thanks