ZTS: Fix Summary Page

The qemu-9-summary-page.sh script reads the file env.txt in the
first lines. When the module didn't build, this file was not copied
into the tarfile - causing the scipt to abort.

Fix: copy needed files into the tarfile in case of module build
failures. The fix ignores also empty tarfiles in future.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes #16555

.github/workflows/scripts/qemu-7-prepare.sh

@@ -18,6 +18,7 @@ if [ -z ${VMs:-} ]; then
   cd $RESPATH
   echo ":exclamation: ZFS module didn't build successfully :exclamation:" \
     | tee summary.txt | tee /tmp/summary.txt
+  cp /var/tmp/*.txt .
   tar cf /tmp/qemu-$OS.tar -C $RESPATH -h . || true
   exit 0
 fi