fix(spanner): Added exception for setUseMultiplexedSessionBlindWrite in Clirr check. Removing this is safe as it's not used by customers.

Author: pratickchokhani

google-cloud-spanner-executor/clirr-ignored-differences.xml

@@ -7,4 +7,9 @@
     <method>CloudExecutorImpl(boolean)</method>
     <to>CloudExecutorImpl(boolean, double)</to>
   </difference>
+  <difference>
+    <differenceType>7002</differenceType>
+    <className>com/google/cloud/spanner/SessionPoolOptionsHelper</className>
+    <method>com.google.cloud.spanner.SessionPoolOptions$Builder setUseMultiplexedSessionBlindWrite(com.google.cloud.spanner.SessionPoolOptions$Builder, boolean)</method>
+  </difference>
 </differences>