Revert of [debugger] debug-evaluate should not not modify local values.

test/mjsunit/debug-evaluate-locals.js

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
 //     * Neither the name of Google Inc. nor the names of its
 //       contributors may be used to endorse or promote products derived
 //       from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (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: --expose-debug-as debug --debug-eval-readonly-locals
+// Flags: --expose-debug-as debug
 // Get the Debug object exposed from the debug context global object.
 Debug = debug.Debug
 
 listenerComplete = false;
 exception = false;
 
 
 function h() {
   var a = 1;
   var b = 2;
@@ skipping 81 matching lines @@
       assertEquals(5, exec_state.frame(0).evaluate('eval').value());
       assertEquals(3, exec_state.frame(1).evaluate('a').value());
       // Reference error because g does not reference b.
       assertThrows(() => exec_state.frame(1).evaluate('b'), ReferenceError);
       assertEquals("function",
                    typeof exec_state.frame(1).evaluate('eval').value());
       assertEquals(5, exec_state.frame(2).evaluate('a').value());
       assertEquals(6, exec_state.frame(2).evaluate('b').value());
       assertEquals("function",
                    typeof exec_state.frame(2).evaluate('eval').value());
-      // Assignments to local variables only have temporary effect.
       assertEquals("foo",
                    exec_state.frame(0).evaluate('a = "foo"').value());
       assertEquals("bar",
                    exec_state.frame(1).evaluate('a = "bar"').value());
       // Indicate that all was processed.
       listenerComplete = true;
     }
   } catch (e) {
     exception = e;
     print("Caught something. " + e + " " + e.stack);
   };
 };
 
 // Add the debug event listener.
 Debug.setListener(listener);
 
 var f_result = f();
 
-assertEquals(4, f_result);
+assertEquals('foobar', f_result);
 
 // Make sure that the debug event listener was invoked.
 assertFalse(exception, "exception in listener")
 assertTrue(listenerComplete);