[test] Regression Sequence Overrides and Filter Genesis Export

This makes a couple tweaks to the regression tests:

1. Support a sequence parameter on all txs so multiple can be sent from the same address in one block
2. Remove the time and version from the genesis exports so that users can just set EXPORT=1 without incurring source changes on all existing exports that only change the version or time
3. Mount tests in regression test container to avoid re-compile and local docker image bloat (only changes to Golang source will trigger new image)