Add the possibility to specify different configs for the same pass
Add the possibility to specify different configs for the same pass

Summary:
As title.

This change introduces the possibility to have the same pass run with different
configurations, when ran multiple times.

Example:
* having `SomePass` used multiple times

  config:

  ...
  "SomePass$1",
  ...
  "SomePass$2",
  ...

  "SomePass$1" : {
    ... configs for the first run
  },
  "SomePass$2" : {
    ... configs for the second run
  }

note: There can be anything after $.

This should change any of the existing logic, as the names are only used to
match with the existing passes.

Reviewed By: minjang, int3, maxmg22

Differential Revision: D6118561

fbshipit-source-id: a411b953efeb72bf351ee194a864c35aa13d65b7

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