[compiler] Make a test more robust

Bug: v8:11666
Change-Id: I7ccb1a888d16202895aa6288b141d3e41b524572
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2835708
Auto-Submit: Georg Neis <neis@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74035}

test/mjsunit/compiler/load-elimination-const-field.js

@@ -134,7 +134,8 @@
         }
     }
 
-    %EnsureFeedbackVectorForFunction(B);
+    %PrepareFunctionForOptimization(B);
+
     %PrepareFunctionForOptimization(inst_param);
     inst_param(1); inst_param(2);
     %OptimizeFunctionOnNextCall(inst_param); inst_param(3);
@@ -165,7 +166,6 @@
         }
     }
 
-    %EnsureFeedbackVectorForFunction(B);
     %PrepareFunctionForOptimization(inst_computed);
     inst_computed(1); inst_computed(2);
     %OptimizeFunctionOnNextCall(inst_computed); inst_computed(3);