Fix a C-style cast to a const_cast<>.  Followup to bug 837957, r=sparky

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extra : rebase_source : f4c806060a89a424544ce5704b19ed36ef968e88
Bug 837957 - Implement ICU dependent functions of Intl.Collator, Intl.NumberFormat, Intl.DateTimeFormat (part 8). r=jwalden

--HG--
extra : rebase_source : 94306c4c0d5950b5d860891d01768e51ef17c9f1
Bug 837957 - Implement ICU dependent functions of Intl.Collator, Intl.NumberFormat, Intl.DateTimeFormat (tests). r=terrence

--HG--
extra : rebase_source : e101ce48506960a2733b9eb5be4065ca5933fd96
Bug 769871 - Reimplement String.localeCompare per ECMA-402.  r=jwalden

--HG--
extra : rebase_source : b6378bff8be8a9cf64fce43dc53ed9baf25738c5
Bug 769871 - Reimplement Number.toLocaleString per ECMA-402. r=jwalden

--HG--
extra : rebase_source : 5a1e5a57e89056d128956cd7d7f2c7ce6b3dec54
Bug 769871 - Reimplement Date.toLocaleString per ECMA-402. r=jwalden

--HG--
extra : rebase_source : 77b0023432502bc4e110143d06c10825fb020190
Bug 851237 - Mark the static-assert typedef with an unused attribute so it doesn't trigger compiler warnings.  r=dholbert

--HG--
extra : rebase_source : 20ad6cd988f2cf5ddedfbb7dd99e368b96c2242a
Bug 851237 - Replace StaticAssert uses with MOZ_STATIC_ASSERT.  r=dholbert

--HG--
extra : rebase_source : d8b9715e05b959b11ee0f645141fd077b8599ab1
Bug 851237 - Convert a static-assertion typedef to MOZ_STATIC_ASSERT.  r=dholbert

--HG--
extra : rebase_source : cb98976842ed2324a6bc93238b28653baacdd083