Add DartType.treatAsRaw to treat List<dynamic> as List in the backend.

sdk/lib/_internal/compiler/implementation/ssa/nodes.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/nodes.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/nodes.dart b/sdk/lib/_internal/compiler/implementation/ssa/nodes.dart
index 8c723df979d07f6c503f9bca782dfa4320fc6892..0ef5bcdb958910fe3673cc83bfcfcedb01009c4c 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/nodes.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/nodes.dart
@@ -1124,7 +1124,7 @@ abstract class HInstruction implements Spannable {
     // instructions with generics. It has the generic type context
     // available.
     assert(type.kind != TypeKind.TYPE_VARIABLE);
-    assert(type.isRaw || type.kind == TypeKind.FUNCTION);
+    assert(type.treatAsRaw || type.kind == TypeKind.FUNCTION);
     if (type.treatAsDynamic) return this;
     if (identical(type.element, compiler.objectClass)) return this;
     if (type.kind != TypeKind.INTERFACE) {
@@ -1132,7 +1132,7 @@ abstract class HInstruction implements Spannable {
     } else if (kind == HTypeConversion.BOOLEAN_CONVERSION_CHECK) {
       // Boolean conversion checks work on non-nullable booleans.
       return new HTypeConversion(type, kind, HType.BOOLEAN, this);
-    } else if (kind == HTypeConversion.CHECKED_MODE_CHECK && !type.isRaw) {
+    } else if (kind == HTypeConversion.CHECKED_MODE_CHECK && !type.treatAsRaw) {
         throw 'creating compound check to $type (this = ${this})';
     } else {
       HType subtype = new HType.subtype(type, compiler);