Always create reproducible builds

When we started introducing some possibly more intrusive compiler flags and functionality for reproducible builds, we also introduced a flag to turn this off out of an abundance of caution. But we have been been using this configuration for a year or so internally within Oracle, with no issues. So there's really no reason to be able to turn this off. (If you were to ask me, the fact that compilers and build tools ever started to produce non-deterministic output has been a bug from day one.)