`IsLess` would incorrectly return true if both `SR_OVERFLOW` and `SR_SIGN` are set, as `(sr & SR_OVERFLOW) != (sr & SR_SIGN)` becomes `SR_OVERFLOW != SR_SIGN` which is true as the two masks are different. This broke in e651592ef5.
This issue only affected the DSP LLE Interpreter, and not the DSP LLE JIT.
I've also included a simple test case for this. `ax0.l` (on the top left) is set to 0 if the instruction following `IFL` does not execute and to 1 if it is executed.