nterp: Address old x86-64 comments.

Follow-up to
    https://android-review.googlesource.com/1185416 ,
    https://android-review.googlesource.com/1180627 .

Test: testrunner.py --host --interpreter
Change-Id: I4ee8825593cf11d673fcaf8e1172d00405cc7abc
2 files changed