Summary:
This test was broken by the tail duplication logic being changed in
r311139, update the test values and add a note about how to properly run
a benchmark to verify that the values are safe to update.
Reviewers: vitalybuka
Reviewed By: vitalybuka
Subscribers: dvyukov, kubamracek
Differential Revision: https://reviews.llvm.org/D36889
llvm-svn: 311189
599b11784a