java being run with -D64 instead of -d64

[jrandall]

https://github.com/wtsi-hgi/arvados-pipelines/blob/master/cwl/tools/gatk-4.0/HaplotypeCaller.cwl#L5

-d64 is an option that tells Java to make sure to use 64 bit mode (although almost certainly it is the default anyway). -D64 might not mean anything, or perhaps it sets a system property named 64 to no value? It is not clear, but it is not the same as -d64:

$ docker run -it mercury/gatk-4.0.0.0:v1 java -h | grep '\-d64'
    -d64          use a 64-bit data model if available
$ docker run -it mercury/gatk-4.0.0.0:v1 java -h | grep -A 1 '\-D'
    -D<name>=<value>
                  set a system property