Revert "dart2js: switching isolate is not 'PURE'"

pkg/compiler/lib/src/ssa/builder.dart

Index: pkg/compiler/lib/src/ssa/builder.dart
diff --git a/pkg/compiler/lib/src/ssa/builder.dart b/pkg/compiler/lib/src/ssa/builder.dart
index 22ef5e1cbb376f88a58e1076a896391c63b95481..540ba50ecb788da3fa36a95bf0376e7cd6538f04 100644
--- a/pkg/compiler/lib/src/ssa/builder.dart
+++ b/pkg/compiler/lib/src/ssa/builder.dart
@@ -4198,11 +4198,9 @@ class SsaBuilder extends ast.Visitor
       // If the isolate library is not used, we just generate code
       // to fetch the static state.
       String name = backend.namer.staticStateHolder;
-      push(new HForeignCode(
-          js.js.parseForeignJS(name),
-          backend.dynamicType,
-          <HInstruction>[],
-          nativeBehavior: native.NativeBehavior.DEPENDS_OTHER));
+      push(new HForeignCode(js.js.parseForeignJS(name),
+                            backend.dynamicType,
+                            <HInstruction>[]));
     } else {
       // Call a helper method from the isolate library. The isolate
       // library uses its own isolate structure, that encapsulates
@@ -4480,7 +4478,7 @@ class SsaBuilder extends ast.Visitor
         js.js.parseForeignJS("$isolateName = #"),
         backend.dynamicType,
         <HInstruction>[pop()],
-        nativeBehavior: native.NativeBehavior.CHANGES_OTHER,
+        nativeBehavior: native.NativeBehavior.PURE,
         effects: sideEffects));
   }
 
@@ -4490,8 +4488,7 @@ class SsaBuilder extends ast.Visitor
     }
     push(new HForeignCode(js.js.parseForeignJS(backend.namer.staticStateHolder),
                           backend.dynamicType,
-                          <HInstruction>[],
-                          nativeBehavior: native.NativeBehavior.DEPENDS_OTHER));
+                          <HInstruction>[]));
   }
 
   void handleForeignSend(ast.Send node, FunctionElement element) {