Resource aggregator should handle missing memory settings

[barkbay]

This PR fixes a bug where a user might want to set some JVM parameters without JVM memory settings (Xmx). To reproduce create the following Elasticsearch resource:

apiVersion: elasticsearch.k8s.elastic.co/v1
kind: Elasticsearch
metadata:
  name: es
spec:
  version: 6.8.21
  nodeSets:
    - name: master
      config:
        node.master: true
        node.data: true
        node.ingest: true
        node.store.allow_mmap: false
      podTemplate:
        spec:
          containers:
            - name: elasticsearch
              env:
                - name: ES_JAVA_OPTS
                  value: "-Dlog4j2.formatMsgNoLookups=true"
      count: 1

Operator logs:

2021-12-14T10:23:36.616+0100    ERROR   resource        Failed to report licensing information
{
  "service.version": "XXXXXXX",
     "error": "failed to aggregate Elasticsearch memory: cannot extract max jvm heap size from -Dlog4j2.formatMsgNoLookups=true", "errorVerbose": "cannot extract max jvm heap size from -Dlog4j2.formatMsgNoLookups=true\n..."
}

This PR also removes unit tests cases where the JVM would not be able to start (Unrecognized option, Invalid maximum heap size ...)

[thbkrkr]

LGTM