This fixes runtime calls emitted by the RawMachineAssembler to use the
correct CEntryStub depending on the return count of runtime functions.
Note that this only affects WIN64 and PPC, where the ABI is different.

R=mythria@chromium.org

Review URL: https://codereview.chromium.org/1528643004

Cr-Commit-Position: refs/heads/master@{#32864}