kernel->ssa: implement assert statements

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

Index: pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
diff --git a/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart b/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
index 86aee00033e96b6efae6aca5aa52479642bf262c..0b54193ad356ab74e563f6de983d88c93ca8e20f 100644
--- a/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
+++ b/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
@@ -255,6 +255,23 @@ class KernelAstAdapter {
       TypeMaskFactory.inferredReturnTypeForElement(
           _backend.helpers.checkConcurrentModificationError, _compiler);
 
+  ir.Procedure get assertHelper =>
+      kernel.functions[_backend.helpers.assertHelper];
+
+  TypeMask get assertHelperReturnType => TypeMaskFactory
+      .inferredReturnTypeForElement(_backend.helpers.assertHelper, _compiler);
+
+  ir.Procedure get assertTest => kernel.functions[_backend.helpers.assertTest];
+
+  TypeMask get assertTestReturnType => TypeMaskFactory
+      .inferredReturnTypeForElement(_backend.helpers.assertTest, _compiler);
+
+  ir.Procedure get assertThrow =>
+      kernel.functions[_backend.helpers.assertThrow];
+
+  TypeMask get assertThrowReturnType => TypeMaskFactory
+      .inferredReturnTypeForElement(_backend.helpers.assertThrow, _compiler);
+
   DartType getDartType(ir.DartType type) {
     return type.accept(_typeConverter);
   }