WIP: Default IsStatic constraints to StaticPtr with -XMonomorphismRestriction

fix #20727

(hls and/or emacs very helpfully auto-reformatted a bunch of code, which i'll return to the original state before i put this up for review)

test with:

{-# LANGUAGE StaticPointers #-}
{-# LANGUAGE MonomorphismRestriction #-}
{-# LANGUAGE OverloadedStrings #-}

import GHC.StaticPtr

xyz_integer = 1
xyz_string = "a"
xyz_static = static 'a'

doesn't work currently:

disambigGroup {
  Integer
  t_aA9[tau:0]
  [[W] $dIsStatic_aA6 {0}:: IsStatic t_aA9[tau:0] (CDictCan)]
newTcEvBinds unique = aJi
disambigGroup failed, will try other default types } Integer
disambigGroup {
  Double
  t_aA9[tau:0]
  [[W] $dIsStatic_aA6 {0}:: IsStatic t_aA9[tau:0] (CDictCan)]
newTcEvBinds unique = aJj
disambigGroup failed, will try other default types } Double
disambigGroup {
  String
  t_aA9[tau:0]
  [[W] $dIsStatic_aA6 {0}:: IsStatic t_aA9[tau:0] (CDictCan)]
newTcEvBinds unique = aJk
disambigGroup failed, will try other default types } String
disambigGroup {
  StaticPtr
  t_aA9[tau:0]
  [[W] $dIsStatic_aA6 {0}:: IsStatic t_aA9[tau:0] (CDictCan)]
newTcEvBinds unique = aJl
disambigGroup failed, will try other default types } StaticPtr

disambigGroup in GHC.Tc.Solver sees the new default but doesn't use it (sanity check: it does fire for String with OverloadedStrings enabled)