Revert "Use interceptors for is-checks (version 2)."

pkg/compiler/lib/src/cps_ir/cps_ir_tracer.dart

Index: pkg/compiler/lib/src/cps_ir/cps_ir_tracer.dart
diff --git a/pkg/compiler/lib/src/cps_ir/cps_ir_tracer.dart b/pkg/compiler/lib/src/cps_ir/cps_ir_tracer.dart
index 2b3c95d7cb8205b95bc3d58e82b31de306c4ae24..a969bdbece7a3e910938cf7400c4c73f8d7cd0dd 100644
--- a/pkg/compiler/lib/src/cps_ir/cps_ir_tracer.dart
+++ b/pkg/compiler/lib/src/cps_ir/cps_ir_tracer.dart
@@ -346,15 +346,7 @@ class IRTracer extends TracerUtil implements cps_ir.Visitor {
   visitTypeTest(cps_ir.TypeTest node) {
     String value = formatReference(node.value);
     String args = node.typeArguments.map(formatReference).join(', ');
-    String interceptor = node.interceptor == null
-        ? ''
-        : ' ${formatReference(node.interceptor)}';
-    return "TypeTest ($value ${node.dartType} ($args)$interceptor)";
-  }
-
-  visitTypeTestViaFlag(cps_ir.TypeTestViaFlag node) {
-    String interceptor = formatReference(node.interceptor);
-    return "TypeTestViaFlag ($interceptor ${node.dartType})";
+    return "TypeTest ($value ${node.dartType} ($args))";
   }
 
   visitApplyBuiltinOperator(cps_ir.ApplyBuiltinOperator node) {
@@ -651,10 +643,6 @@ class BlockCollector implements cps_ir.Visitor {
     unexpectedNode(node);
   }
 
-  visitTypeTestViaFlag(cps_ir.TypeTestViaFlag node) {
-    unexpectedNode(node);
-  }
-
   visitApplyBuiltinOperator(cps_ir.ApplyBuiltinOperator node) {
     unexpectedNode(node);
   }