Get rid of old code for union/intersection in HType.

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

Index: sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart b/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
index 1169e1d61a9f7153184e5b6d1e76d619d8502c4f..c9ec6ff608762238fbdad3e674cf85f2cc2fd9f2 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/codegen.dart
@@ -1623,7 +1623,6 @@ abstract class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
     if (target != null) {
       // If we know we're calling a specific method, register that
       // method only.
-      assert(selector.mask != null);
       world.registerDynamicInvocationOf(target, selector);
     } else {
       SourceString name = node.selector.name;
@@ -1737,8 +1736,7 @@ abstract class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
   visitFieldSet(HFieldSet node) {
     Element element = node.element;
     String name = _fieldPropertyName(element);
-    DartType type = node.receiver.instructionType.computeType(compiler);
-    if (type != null && !identical(type.kind, TypeKind.MALFORMED_TYPE)) {
+    if (!node.receiver.instructionType.isUnknown()) {
       // Field setters in the generative constructor body are handled in a
       // step "SsaConstructionFieldTypes" in the ssa optimizer.
       if (!work.element.isGenerativeConstructorBody()) {