Remove leftover print statement in SpannerIO (apache#33200)

Author: Abacn

Diff for: sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/spanner/ReadOperation.java

@@ -135,7 +135,6 @@ String tryGetTableName() {
       return getTable();
     } else if (getQuery() != null) {
       String query = getQuery().getSql();
-      System.err.println(query);
       Matcher matcher = queryPattern.matcher(query);
       if (matcher.find()) {
         return matcher.group("table");