Illformed appmaps get generated

There are circumstances where the events section of an appmap created by appmap-java is not created correctly.

For example, the appmap for org.elasticsearch.search.aggregations.bucket.terms.BytesKeyedBucketOrdsTests contains the sequences 74},,{" and $"},]}:

Alans-MacBook-Pro org.elasticsearch.search.aggregations$ tail -c+470630560 testExplicitCollectsFromSingleBucket.appmap.json | head -100
tic":false,"thread_id":74},,{"$ref":"$"},{"$ref":"$"},{"$ref":"$"},{"$ref":"$"},{"$ref":"$"},{"$ref":"$"},{"$ref":"$"},{"$ref":"$"},{"$ref":"$"},{"$ref":"$"},{"$ref":"$"},{"$ref":"$"},{"$ref":"$"},]}

The appmap for org.elasticsearch.search.aggregations.metrics.HyperLogLogPlusPlusTests.testMerge contains the sequence ":[,{":

Alans-MacBook-Pro org.elasticsearch.search.aggregations$ tail -c+$(expr 427988011 - 50) testMerge.appmap.json | head -c+200 | less
"lineno":72,"method_id":"readIntLE","parameters":[,{"defined_class":"org.elasticsearch.common.util.AbstractBigArray","event":"return","id":1159599,"lineno":81,"method_id":"size","path":"src/main/java/

The appmap for org.elasticsearch.search.aggregations.metrics.MedianAbsoluteDeviationAggregatorTests contains the sequence main/java,{"defined_class":":

Alans-MacBook-Pro org.elasticsearch.search.aggregations$ tail -c+$(expr 4692538 - 100) testSomeMatchesSortedNumericDocValues.appmap.json | head -c+150
"object_id":719878273,"value":"[Ljava.lang.String;@2ae87881"}],"path":"src/main/java,{"defined_class":"org.elasticsearch.common.settings.AbstractScope

It's possible that there were errors generated during the execution of these tests.

Start by reproducing appmap generation with the listed Elasticsearch tests, including BytesKeyedBucketOrdsTests, HyperLogLogPlusPlusTests.testMerge, and MedianAbsoluteDeviationAggregatorTests. Inspect the generated events sections around the reported byte sequences and compare them with valid JSON structure. Done means these tests no longer produce malformed appmap files.