chore(spanner): review comments

Author: harshachinta

google-cloud-spanner/src/main/java/com/google/cloud/spanner/TransactionRunnerImpl.java

@@ -501,8 +501,6 @@ public void run() {
                     onPrecommitToken(proto.getPrecommitToken());
                     span.addAnnotation(
                         "Commit operation will be retried with new precommit token as the CommitResponse includes a MultiplexedSessionRetry field");
-                    opSpan.addAnnotation(
-                        "Commit operation will be retried with new precommit token as the CommitResponse includes a MultiplexedSessionRetry field");
                     opSpan.end();
 
                     // Retry the commit RPC with the latest precommit token from CommitResponse.

google-cloud-spanner/src/test/java/com/google/cloud/spanner/MultiplexedSessionDatabaseClientMockServerTest.java

@@ -1618,13 +1618,17 @@ public void testReadWriteTransactionWithCommitRetryProtocolExtensionSet() {
     assertEquals(
         ByteString.copyFromUtf8("PartialResultSetPrecommitToken"),
         commitRequests.get(0).getPrecommitToken().getPrecommitToken());
+    // Verify that the first request has mutations set
+    assertTrue(commitRequests.get(0).getMutationsCount() > 0);
 
     // Second CommitRequest should contain the latest precommit token received via the
     // CommitResponse in previous attempt.
     assertNotNull(commitRequests.get(1).getPrecommitToken());
     assertEquals(
         ByteString.copyFromUtf8("CommitResponsePrecommitToken"),
         commitRequests.get(1).getPrecommitToken().getPrecommitToken());
+    // Verify that the commit retry request does not have any mutations set
+    assertEquals(0, commitRequests.get(1).getMutationsCount());
 
     assertNotNull(client.multiplexedSessionDatabaseClient);
     assertEquals(1L, client.multiplexedSessionDatabaseClient.getNumSessionsAcquired().get());