The .lck file filename length needs to be less than 255 bytes (not symbols) on
linux, and it was still too long on this test, because of the
subdir=測試_Русский_{spc}_{spc}_ě_áñ
Before this change, integration tests often could not be run on backends with
differing features from the local system that goldenized them. In particular,
differences in modtime precision, checksum support, and encoding would cause
false positives. After this change, the tests more accurately account for the
features of the backend being tested, which allows us to see true positives
more clearly, and more meaningfully assess whether a backend is supported.
