Exponetially increase the sleep before retrying commit on the GTM.
Exponetially increase the sleep before retrying commit on the GTM.

When a transaction waits for another transaction to complete, we enforce the
same ordering on the same GTM by making the former transaction wait on the
latter. We do this by a simple retry logic. While the latter transaction should
ideally finish soon because it has already finished on the datanode, the retry
loop now waits exponentially, starting at 1000usec but limited by 1s.

Patch by Mason Sharp

zeroae/postgres-xl,zeroae/postgres-xl,zeroae/postgres-xl,zeroae/postgres-xl,zeroae/postgres-xl