* Mark arith011 as broken with integer-simple

   As noted in #16091, arith011 fails when run against integer-simple with a
   "divide by zero" exception. This suggests that integer-gmp and integer-simple
   are handling division by zero differently.

 * This also fixes broken_without_gmp; the lack of types made the previous
   failure silent, sadly. Improves situation of #16043.

 * Mark several tests implicitly depending upon integer-gmp as broken
   with integer-simple. These expect to see Core coming from integer-gmp,
   which breaks with integer-simple.

 * Increase runtime timeout multiplier of T11627a with integer-simple

   I previously saw that T11627a timed out in all profiling ways when run against
   integer-simple. I suspect this is due to integer-simple's rather verbose heap
   representation. Let's see whether increasing the runtime timeout helps.

   Fixes test for #11627.

This is all in service of fixing #16043.