chore(spanner): fix tests

Author: harshachinta

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

@@ -3093,14 +3093,15 @@ public void testDatabaseOrInstanceDoesNotExistOnCreate() {
                         .readWriteTransaction()
                         .run(transaction -> transaction.executeUpdate(UPDATE_STATEMENT)));
             // No additional requests should have been sent by the client.
+            // Note that in case of the use of multiplexed sessions, then we have 2 requests:
             // Note that in case of the use of regular sessions, then we have 1 request:
             // 1. BatchCreateSessions for the session pool.
-            // Note that in case of the use of multiplexed sessions for read-only and read-write,
-            // then we have 1 request:
-            // 1. CreateSession for the multiplexed session.
-            // There will be no BatchCreateSessions request in case of multiplexed sessions, because
-            // the session pool options has min size of 0.
-            assertThat(mockSpanner.getRequests()).hasSize(2);
+            // 2. CreateSession for the multiplexed session.
+            assertThat(mockSpanner.getRequests())
+                .hasSize(
+                    spanner.getOptions().getSessionPoolOptions().getUseMultiplexedSession()
+                        ? 2
+                        : 1);
           }
         }
         mockSpanner.reset();