selftests/powerpc: Remove Power9 paste tests

Paste on POWER9 only works to accelerators and not on real memory. So
these tests just generate a SIGILL.

So just delete them.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>