make run_pass on DexClassesVector not pure virtual to transistion to DexStores
make run_pass on DexClassesVector not pure virtual to transistion to DexStores

Summary:
This is the first step to transition the run_pass method in the optimizations use the DexStoresVector prototype rather than a DexClassesVector.  After all of the optimizations are transitioned, I'll remove the run_pass(DexClassesVector...) and make run_pass(DexStoresVector...) pure virtual.
depends on D3666238

Reviewed By: dariorussi

Differential Revision: D3674109

fbshipit-source-id: 1b2e99566c09f2364789c0b8adf9d22e2eddc7a1

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