op-e2e: Recover gracefully from log-after-exit panics (#13190)

* op-e2e: Recover gracefully from log-after-exit panics

There are a lot of places where we log after tests exit. This PR recovers from those panics so tests can continue.

* add helper

op-service/testlog/testlog.go

@@ -159,11 +159,22 @@ func (l *logger) flush() {
 
 	scanner := bufio.NewScanner(l.buf)
 	for scanner.Scan() {
-		l.t.Logf("%*s%s", padding, "", scanner.Text())
+		l.internalFlush("%*s%s", padding, "", scanner.Text())
 	}
 	l.buf.Reset()
 }
 
+func (l *logger) internalFlush(format string, args ...any) {
+	defer func() {
+		if r := recover(); r != nil {
+			log.Warn("testlog: panic during flush", "recover", r)
+		}
+	}()
+
+	l.t.Helper()
+	l.t.Logf(format, args...)
+}
+
 // The Go testing lib uses the runtime package to get info about the calling site, and then decorates the line.
 // We can't disable this decoration, but we can adjust the contents to align by padding after the info.
 // To pad the right amount, we estimate how long the info is.