[stubs] Drop StoreICStub and StoreICTrampolineStub (the non-TurboFan implementations of StoreIC dispatchers).

Because of the planned improvements of IC system it does not make sense to
keep the old platform version of the stub around.

Review-Url: https://codereview.chromium.org/2413653003
Cr-Commit-Position: refs/heads/master@{#40216}