Deoptimize context value in Turbofan (and Crankshaft).

test/mjsunit/debug-step-2.js

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 // Flags: --expose-debug-as debug
+// Flags: --turbo-deoptimization
 
 // This test tests that full code compiled without debug break slots
 // is recompiled with debug break slots when debugging is started.
 
 // Get the Debug object exposed from the debug context global object.
 Debug = debug.Debug
 
 var bp;
 var done = false;
 var step_count = 0;
@@ skipping 41 matching lines @@
 assertEquals(4, step_count);
 
 // Clear the breakpoint and check that no stepping happens.
 Debug.clearBreakPoint(bp);
 prepare_step_test();
 f();
 assertEquals(0, step_count);
 
 // Get rid of the debug event listener.
 Debug.setListener(null);