Merge scripts to fetch or update source repositories

[keithc-ca]

• eliminate repetitive option processing
• ignore '--parallel' option
• handle special openssl options and treat like other repos
• remove old, unused scripts

This is a back-port of https://github.com/ibmruntimes/openj9-openjdk-jdk/pull/781.

[pshipton]

jenkins compile amac jdk11