[Tempest] Create heavy scenario resources in parallel

Manila Tempest scenario tests create all resources one by one and they
are very slow because of it.
Therefore, make all resource 'waiters' run after all resource creation
requests are sent.

Change-Id: I435a5d04bce340b0a2c0a2d30fa5a99e50b311e1
Closes-Bug: #1493405
2 files changed
tree: f87afd24032a00a9c1d033c2a1ecc4f44061ba96
  1. manila_tempest_tests/