Revert "Fix language tests wrt. warnings."

tests/language/double_to_string_as_precision2_test.dart

Index: tests/language/double_to_string_as_precision2_test.dart
diff --git a/tests/language/double_to_string_as_precision2_test.dart b/tests/language/double_to_string_as_precision2_test.dart
index 81520f76bfbbb962edcd18ee7fa3b70676a01895..a2f78f035ab1e68b870d42b6bcc479ef430f7bdf 100644
--- a/tests/language/double_to_string_as_precision2_test.dart
+++ b/tests/language/double_to_string_as_precision2_test.dart
@@ -6,18 +6,17 @@
 import "package:expect/expect.dart";
 
 main() {
-  var v = 0.0;
-  Expect.throws(() => v.toStringAsPrecision(0),
+  Expect.throws(() => 0.0.toStringAsPrecision(0),
                 (e) => e is RangeError);
-  Expect.throws(() => v.toStringAsPrecision(22),
+  Expect.throws(() => 0.0.toStringAsPrecision(22),
                 (e) => e is RangeError);
-  Expect.throws(() => v.toStringAsPrecision(null),
+  Expect.throws(() => 0.0.toStringAsPrecision(null),
                 (e) => e is ArgumentError);
-  Expect.throws(() => v.toStringAsPrecision(1.5),
+  Expect.throws(() => 0.0.toStringAsPrecision(1.5),
                 (e) => e is ArgumentError || e is TypeError);
-  Expect.throws(() => v.toStringAsPrecision("string"),
+  Expect.throws(() => 0.0.toStringAsPrecision("string"),
                 (e) => e is ArgumentError || e is TypeError);
-  Expect.throws(() => v.toStringAsPrecision("3"),
+  Expect.throws(() => 0.0.toStringAsPrecision("3"),
                 (e) => e is ArgumentError || e is TypeError);
 
 }