Keep surefire reports from a failed run

redirectTestOutputToFile is on, so a test that stops before printing anything to
the job log leaves its only record in target/surefire-reports, which the runner
discards with the workspace. That includes the .dump thread dump Surefire writes
when it kills a timed-out fork.

.github/workflows/maven-verify.yml

diff --git a/.github/workflows/maven-verify.yml b/.github/workflows/maven-verify.yml
index 688eff1..99718d8 100644
--- a/.github/workflows/maven-verify.yml
+++ b/.github/workflows/maven-verify.yml
@@ -31,3 +31,6 @@
       jdk-matrix: '[ "17", "21", "26" ]'
       maven4-enabled: true
       maven4-version: '4.0.0-rc-6' # the same as used in project
+      # redirectTestOutputToFile keeps per-test output out of the job log, so on a failure the
+      # reports are the only record of what the test printed before it stopped.
+      failure-upload-path: '**/target/surefire-reports'