Move DualPivotQuicksort from coreimpl to core as _Sort.

lib/compiler/implementation/lib/interceptors.dart

Index: lib/compiler/implementation/lib/interceptors.dart
diff --git a/lib/compiler/implementation/lib/interceptors.dart b/lib/compiler/implementation/lib/interceptors.dart
index 4304e154308f0f5d3b32b224f4169c296e9e5eb2..53243c922015f8168718d0cc7415dabac87e15b1 100644
--- a/lib/compiler/implementation/lib/interceptors.dart
+++ b/lib/compiler/implementation/lib/interceptors.dart
@@ -364,13 +364,13 @@ every(receiver, f) {
 sort$0(receiver) {
   if (!isJsArray(receiver)) return UNINTERCEPTED(receiver.sort());
   checkMutable(receiver, 'sort');
-  DualPivotQuicksort.sort(receiver, Comparable.compare);
+  coreSort(receiver, Comparable.compare);
 }
 
 sort$1(receiver, compare) {
   if (!isJsArray(receiver)) return UNINTERCEPTED(receiver.sort(compare));
   checkMutable(receiver, 'sort');
-  DualPivotQuicksort.sort(receiver, compare);
+  coreSort(receiver, compare);
 }
 
 isNegative(receiver) {