DTtrace test suite driver: execute the verifying script generated by test case

[lwhsu]

Summary

The test case common.funcs.t_dtrace_contrib.tst_basename_d generates a verifying
script which needs to be run to complete the test.

While here, add missing shebang.

Test Plan

cd /usr/tests/cddl/usr.sbin/dtrace && kyua test

This depends on D11707 which fixes common.funcs.t_dtrace_contrib.tst_basename_d

[markj]

cddl/usr.sbin/dtrace/tests/tools/dtest.sh

90 ↗

(On Diff #31136)

I don't see why we're suppressing stderr here. Don't we want to see it? I would instead write:

head -n 1 $STDOUT | grep -q -E <regexp>

[lwhsu]

cddl/usr.sbin/dtrace/tests/tools/dtest.sh

90 ↗

(On Diff #31136)

I originally though it suppress the case that STDOUT does not exist, but now I think it's also fine to yell when that does happen. The 2nd suppressing is similar.

[lwhsu]

• Remove unnecessary stderr suppressing
• Use -q to suppress grep(1) output