Seed random numbers in each process based on pid.

This causes get_unused_port_or_die to try different port numbers in each
concurrently running tests, and consequently enables some parallelism of test
processes.
	Change on 2015/01/05 by ctiller <ctiller@google.com>
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=83289374
4 files changed