Replace std::trunc() with trunc() to support cross-compiling

Fix-up of https://codereview.chromium.org/1965443003 required for
certain toolchains that do not support std::trunc().

BUG=

Review-Url: https://codereview.chromium.org/2056693002
Cr-Commit-Position: refs/heads/master@{#36882}

src/runtime/runtime-simd.cc

@@ -26,7 +26,7 @@ static bool CanCast(F from) {
   // A float can't represent 2^31 - 1 or 2^32 - 1 exactly, so promote the limits
   // to double. Otherwise, the limit is truncated and numbers like 2^31 or 2^32
   // get through, causing any static_cast to be undefined.
-  from = std::trunc(from);
+  from = trunc(from);
   return from >= static_cast<double>(std::numeric_limits<T>::min()) &&
          from <= static_cast<double>(std::numeric_limits<T>::max());
 }