[Bug target/106545] peephole.md seems like it should not exist

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106545

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note I see XTheadMemPair code has been added to peephole.md which is good to
have it away. 
But again the first peephole is also handled differently already via
zero_extendsidi2_shifted which was added in r11-745-gd5cdcd5cf2b292 but it was
not until r13-4907-g2e886eef7f2b5a when we started to optimizing the following
code:
unsigned long f(unsigned long a)
{
  a <<= 32;
  a >>= 32;
  a <<= 10;
  return a;
}