Merged PRs

• 886: no parallelism if GOMAXPROCS == 1
• 885: cpp mysql client tests
• 883: mysql client tests install golang
• 878: Go MySQL client test
• 877: validate ref strings when resolving ref specs
  fix for #874
• 875: go: Changes to support some commit walks used in Dolthub diffs when the commits come from different repositories.
• 874: Added skip bats test for ref spec panic on diff
• 873: Fixed ActionExecutor causing duplicate key error loop
• 870: Fixed bug with diffing column defaults
• 869: update vitess
• 868: Added perl mysql client tests
• 867: Added Python SQLAlchemy test to mysql-client-tests
• 190: Harrison pr
  https://github.com/liquidata-inc/go-mysql-server/pull/189/files and a couple fixes
• 188: triggers 2
  Insert triggers working for the following cases:
  • Insert some rows
  • Delete some rows
  • Update some rows
    Missing, needs to be added:
  • set new.x = blah as part of a BEFORE INSERT trigger. Need to rewrite the SET handling parser logic for that.
  • error testing for bad triggers (like inserting on the same table the trigger is defined on)
    As part of this, I rewrote the execution logic for Update, Delete, and Insert entirely.