[Bug c/123212] GCC 15 no longer compiles switch statements to jump tables by default with Og

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123212

--- Comment #1 from Sam James <sjames at gcc dot gnu.org> ---
The algorithm was changed for switch conversion in 15 and then in
r15-4756-g06bc3a734e8890, it was made to only be at >= -O1 (but not -Og)
because of it being too expensive at -O0.