Speedup stringsearch for two byte strings
Uses the lower byte with memchr which is
significantly faster than a naive compare
Performance difference with bench (http://hastebin.com/xuxexataso.js):
old new
single character single character
Κ found at 922 Κ found at 922
3324 616
㎡ found at 13217 ㎡ found at 13217
42366 4931
က found at 4096 က found at 4096
13369 9836
found at 65280 found at 65280
207472 36149
ᆬ found at 65445 ᆬ found at 65445
209344 36666
found at 8197 found at 8197
26731 11757
倂 found at 20482 倂 found at 20482
66071 17193
linear search linear search
ΚΛ found at 922 ΚΛ found at 922
4112 504
㎡㎢ found at 13217 ㎡㎢ found at 13217
55105 5119
ᆬᆭ found at 65445 ᆬᆭ found at 65445
268016 35496
linear + bmh search linear + bmh search
ΚΛΜΝΞΟΠΡ found at 922 ΚΛΜΝΞΟΠΡ found at 922
2897 522
ᆬᆭᄃᄄᄅᆰᆱᆲ found at 65445 ᆬᆭᄃᄄᄅᆰᆱᆲ found at 65445
167687 158465
Review URL: https://codereview.chromium.org/
1303033012
Cr-Commit-Position: refs/heads/master@{#30587}