mac: Fix spellcheck test on OSX 10.10.

The OSX 10.10 dictionary changed its suggested corrections to "bouy", which
used to include "buoy". I updated the test to check that "bouy" has the
suggested correction "bout", which is present in the dictionary for both OSX
10.9 and OSX 10.10.

BUG=390276

Review URL: https://codereview.chromium.org/591313002

Cr-Commit-Position: refs/heads/master@{#296626}

chrome/browser/spellchecker/spellcheck_platform_mac_unittest.cc

@@ -136,7 +136,10 @@ TEST_F(SpellcheckMacTest, SpellCheckSuggestions_EN_US) {
     {"beleive", "believe"},
     {"bellweather", "bellwether"},
     {"benifit", "benefit"},
-    {"bouy", "buoy"},
+    // This particular spelling correction was removed in OSX 10.10. Replacing
+    // it with another spelling correction that also works on older OSes.
+    // {"bouy", "buoy"},
+    {"bouy", "body"},
     {"briliant", "brilliant"},
     {"burgler", "burglar"},
     {"camoflage", "camouflage"},