virtual-function-elimination leads to unstable assembly code

[Jujstme]

As described in the book, VFE tends to remove vtable functions too eagerly, leading to miscompilations, with situations that will trigger panics despite using completely safe code.

An example is provided by the following code, which is completely safe and correct from a language standpoint on std, but will trigger a panic upon calling the .to_string() function

In these cases you might want to remove the flag declared in here altogether.