[mjsunit] Remove unsupported flag --turbo-deoptimization from tests.

test/mjsunit/regress/regress-assignment-in-test-context.js

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --allow-natives-syntax --always-opt
-// Flags: --turbo-filter=* --turbo-deoptimization
+// Flags: --allow-natives-syntax --always-opt --turbo-filter=*
 
 function assertEquals() {}
 
 function f(o) {
   if (o.setterProperty = 0) {
     return 1;
   }
   return 2;
 }
 
 function deopt() { %DeoptimizeFunction(f); }
 
 assertEquals(2,
              f(Object.defineProperty({}, "setterProperty", { set: deopt })));