ktest: Add logfile to failure directory

The logfile contains a lot of useful information about the tests being
run. Add it to the stored failure directory when the test fails.

Cc: John 'Warthog9' Hawley <warthog9@kernel.org>
Link: https://patch.msgid.link/20260420142315.7bbc3624@fedora
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

tools/testing/ktest/ktest.pl

@@ -1878,6 +1878,12 @@ sub save_logs {
 	"testlog" => $testlog,
     );
 
+    if (defined($opt{"LOG_FILE"})) {
+	if (-f $opt{"LOG_FILE"}) {
+	    cp $opt{"LOG_FILE"}, "$dir/logfile";
+	}
+    }
+
     while (my ($name, $source) = each(%files)) {
 	if (-f "$source") {
 	    cp "$source", "$dir/$name" or