Further reduce use of Compiler.closedWorld.

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

Index: pkg/compiler/lib/src/ssa/nodes.dart
diff --git a/pkg/compiler/lib/src/ssa/nodes.dart b/pkg/compiler/lib/src/ssa/nodes.dart
index 83ecc44dca5ef1fa641f1c9b4e40d7d7649298d3..61eec684575a0484fda24631f5b9968299b2898c 100644
--- a/pkg/compiler/lib/src/ssa/nodes.dart
+++ b/pkg/compiler/lib/src/ssa/nodes.dart
@@ -216,7 +216,8 @@ class HGraph {
         // We use `null` as the value for invalid constant expressions.
         constant = const NullConstantValue();
       }
-      TypeMask type = computeTypeMask(compiler, constant);
+      TypeMask type =
+          computeTypeMask(compiler.closedWorld, compiler.backend, constant);
       result = new HConstant.internal(constant, type)
         ..sourceInformation = sourceInformation;
       entry.addAtExit(result);