Merge third_party/smhasher/src from https://chromium.googlesource.com/external/smhasher.git at e87738e57558e0ec472b2fc3a643b838e5b6e88f

This commit was generated by merge_from_chromium.py.

Change-Id: Ie20768ee3b487da76fa6721313bae2b77e28ef4b