lots of really bad hacks, here

lots of really bad hacks, here
https://bugs.libre-soc.org/show_bug.cgi?id=933
1) rename to "pcdec." because it always sets CR0. following the convention
   set by "stbcx." etc.
2) hacked ISACaller into submission because this is the first instruction
   supported with "." at the end which is not Rc=1
3) handle_comparison was bypassed when CR0 is detected as explicitly
   an output: there is no point computing Rc=1 EQ/LT/GT/SO when CR0
   is supplied by the pseudocode
4) the test case case_pcdec_simple() was not making explicit deepcopy()
   of the registers, which causes problems
5) various places in actually getting the instruction from the insn
   dictionary, have to special-case "pcdec."
6) sv/trans/svp64.py updated to name "pcdec."
.