Update mock SDK 'double'.

pkg/analyzer/test/src/context/mock_sdk.dart

Index: pkg/analyzer/test/src/context/mock_sdk.dart
diff --git a/pkg/analyzer/test/src/context/mock_sdk.dart b/pkg/analyzer/test/src/context/mock_sdk.dart
index e7021f0e87daac51e081dba163095c1061eee8f8..6539e675a1a3c836262f934fb61db67c5e76e7bd 100644
--- a/pkg/analyzer/test/src/context/mock_sdk.dart
+++ b/pkg/analyzer/test/src/context/mock_sdk.dart
@@ -141,7 +141,36 @@ abstract class int extends num {
                             { int radix,
                               int onError(String source) });
 }
-class double extends num {}
+
+abstract class double extends num {
+  static const double NAN = 0.0 / 0.0;
+  static const double INFINITY = 1.0 / 0.0;
+  static const double NEGATIVE_INFINITY = -INFINITY;
+  static const double MIN_POSITIVE = 5e-324;
+  static const double MAX_FINITE = 1.7976931348623157e+308;
+
+  double remainder(num other);
+  double operator +(num other);
+  double operator -(num other);
+  double operator *(num other);
+  double operator %(num other);
+  double operator /(num other);
+  int operator ~/(num other);
+  double operator -();
+  double abs();
+  double get sign;
+  int round();
+  int floor();
+  int ceil();
+  int truncate();
+  double roundToDouble();
+  double floorToDouble();
+  double ceilToDouble();
+  double truncateToDouble();
+  external static double parse(String source,
+                               [double onError(String source)]);
+}
+
 class DateTime extends Object {}
 class Null extends Object {}