:sdks:java:testing:nexmark:javadoc prints warnings.

It doesn't cause failures, but these logs are distracting to see in unrelated test runs.

It's having problems resolving symbols for some reason.

09:39:30 /home/jenkins/jenkins-slave/workspace/beam_PreCommit_SQL_Phrase/src/sdks/java/testing/nexmark/src/main/java/org/apache/beam/sdk/nexmark/queries/Query5.java:68: error: cannot find symbol
09:39:30 extends AccumulatingCombineFn, Accum, KV\>\> {
09:39:30 ^
09:39:30 symbol: class AccumulatingCombineFn
09:39:30 location: class Query5
09:39:30 /home/jenkins/jenkins-slave/workspace/beam_PreCommit_SQL_Phrase/src/sdks/java/testing/nexmark/src/main/java/org/apache/beam/sdk/nexmark/queries/Query5.java:68: error: cannot find symbol
09:39:30 extends AccumulatingCombineFn, Accum, KV\>\> {
09:39:30 ^
09:39:30 symbol: class KV
09:39:30 location: class Query5
09:39:30 /home/jenkins/jenkins-slave/workspace/beam_PreCommit_SQL_Phrase/src/sdks/java/testing/nexmark/src/main/java/org/apache/beam/sdk/nexmark/queries/Query5.java:68: error: cannot find symbol
09:39:30 extends AccumulatingCombineFn, Accum, KV\>\> {
09:39:30 ^
09:39:30 symbol: class Accum
09:39:30 location: class Query5
09:39:30 /home/jenkins/jenkins-slave/workspace/beam_PreCommit_SQL_Phrase/src/sdks/java/testing/nexmark/src/main/java/org/apache/beam/sdk/nexmark/queries/Query5.java:68: error: cannot find symbol
09:39:30 extends AccumulatingCombineFn, Accum, KV\>\> {
09:39:30 ^
09:39:30 symbol: class KV
09:39:30 location: class Query5
09:39:32 4 warnings

Imported from Jira [BEAM-12330](https://issues.apache.org/jira/browse/BEAM-12330). Original Jira may contain additional context.
Reported by: ibzib.