Implement missing YARV bytecodes

[mgaudet]

Currently, a number of YARV bytecodes remain unimplemented in the Ruby JIT.

The list (as of dd6dae0) is:

• [x] getclassvariable
• [x] setclassvariable
• [x] putiseq
• [x] freezestring
• [ ] reverse (see below)
• [ ] checkkeyword
• [ ] defineclass
• [ ] opt_str_freeze
• [ ] opt_newarray_max
• [ ] opt_newarray_min
• [ ] branchnil
• [x] getinlinecache
• [x] setinlinecache
• [ ] once
• [x] opt_case_dispatch
• [ ] opt_call_c_function
• [ ] bitblt

[mgaudet]

Just updated the list above to be the complete list (along with a reference revision)

[mgaudet]

For reference, from optcarrot, here are the aborts:

magaudet@ubuntu1604VM:~/open/optcarrot (master)$ OMR_JIT_OPTIONS=-Xjit:count=0,staticDebugCounters={*unsupported*} LD_LIBRARY_PATH=~/open/ruby_24/ ~/open/ruby_24/ruby --disable-gems  -v -Ilib -r./tools/shim bin/optcarrot --headless --print-fps --print-video-checksum --frames 180  examples/Lan_Master.nes
<snip> 

== Static debug counters ==
  1: compilation_abort/unsupported_instruction                   |          142 |    100.00% |  __   1 __
  2: compilation_abort/unsupported_instruction/defineclass       |           16 |     11.27% |    11.27% |  __   2 __
  3: compilation_abort/unsupported_instruction/getinlinecache    |          122 |     85.92% |    85.92% |  __   3 __
  4: compilation_abort/unsupported_instruction/opt_case_dispatch |            3 |      2.11% |     2.11% |  __   4 __
  5: compilation_abort/unsupported_instruction/opt_newarray_min  |            1 |      0.70% |     0.70% |  __   5 __

[mgaudet]

I have a preliminary implementation of the reverse opcode, however, until #42 is resolved, I probably won't commit it -- I have essentially no evidence it works, because I don't currently know how to get it generated.

That implementation, for reference though, is here.