This fixes occurences of a loop variable being captured in parallel
tests. With the previous code, only the last test case is actually
exercised. To work around this problem, we create a local copy of the
range variable before the parallel test, as suggested in the
documentation for the `testing` package:
https://pkg.go.dev/testing#hdr-Subtests_and_Sub_benchmarks
Issues were found automatically using the `loopvarcapture` linter.
Renato Costa
ec3d2ef360