[tests] Cleanup tests that use assertOptimized()/assertUnoptimized().

test/mjsunit/es6/block-let-crankshaft.js

Index: test/mjsunit/es6/block-let-crankshaft.js
diff --git a/test/mjsunit/es6/block-let-crankshaft.js b/test/mjsunit/es6/block-let-crankshaft.js
index 9cfdf847fcccf50aa54bdab3b6d590401c8ec0ed..99a8b52968fce4d8d90e64c0109541fa6755f707 100644
--- a/test/mjsunit/es6/block-let-crankshaft.js
+++ b/test/mjsunit/es6/block-let-crankshaft.js
@@ -25,7 +25,7 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Flags: --allow-natives-syntax
+// Flags: --allow-natives-syntax --crankshaft
 
 "use strict";
 
@@ -480,5 +480,5 @@ for (var i=0; i<10; i++) {
 f(12);
 g(12);
 
-assertTrue(%GetOptimizationStatus(f) != 2);
-assertTrue(%GetOptimizationStatus(g) != 2);
+assertOptimized(f);
+assertOptimized(g);