Add fine-grained diff implementation to LiveEdit engine.

test/mjsunit/debug-liveedit-newsource.js

Index: test/mjsunit/debug-liveedit-newsource.js
diff --git a/test/mjsunit/debug-liveedit-newsource.js b/test/mjsunit/debug-liveedit-newsource.js
index 7b8945a7056fec2ba2bfd3615fd95575c3d04154..a60e69f902114fdbedebffa820cd6cdc56a93e7c 100644
--- a/test/mjsunit/debug-liveedit-newsource.js
+++ b/test/mjsunit/debug-liveedit-newsource.js
@@ -64,6 +64,6 @@ print("Change log: " + JSON.stringify(change_log) + "\n");
 assertEquals("Capybara", ChooseAnimal());
 // Global variable do not get changed (without restarting script).
 assertEquals(25, something1);
-// Function is oneliner, so currently it is treated as damaged and not patched.
-assertEquals(17, ChooseNumber());
+// We should support changes in oneliners.
+assertEquals(18, ChooseNumber());
 assertEquals("Hello Peter", ChooseAnimal.Factory()("Peter"));