Implement volatile address registers. Fixes quite some tests, but also breaks others... (overall more are fixed than are broken :) )

paramgr.pas, tparamanager:
  + add virtual get_volatile_registers_address method which by default returns an empty set
cgobj.pas, tcg:
  * allocallcpuregisters: also allocate address registers if needed
  * deallocallcpuregisters: also deallocate address registers if needed
ncgcal.pas, tcgcallnode.pass_generate_code:
  * (de)allocate address registers
  * keep result from being deallocated if it should be an address register (currently by no architecture...)
m68k/cpupara.pas, tm68kparamanager:
  + get_volatile_registers_address: return a0 and a1 as volatile registers
m68k/n68kmat.pas, tm68kmoddivnode.call_rtl_divmod_reg_reg:
  * (de)allocate address registers


git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@25633 3ad0048d-3df7-0310-abae-a5850022a9f2