move test reinit to mocha's after hooks

[alxndrsn]

Closes #499

This will fail the whole suite fast if initialize() times out in a single test. IMO this is helpful, as otherwise the state of the database is unpredictable for subsequent tests.

Example failure:

  1 failing

  1) "before each" hook for "should reject forms created while project managed encryption is being enabled @slow":
     Error: Failed to reinitalize after previous test: 'managed encryption lock management should reject keyless forms in keyed projects @slow'.  You may need to increase your mocha timeout.
      at Context.<anonymous> (test/integration/setup.js:80:29)
      at processImmediate (internal/timers.js:464:21)