Simply use DISPATCH_ORIGINAL_INSN instead of rb_funcall. This is,
when possible, overall performant because method dispatch results are
cached inside of CALL_CACHE. Should also be good for JIT.
----
trunk: ruby 2.6.0dev (2018-09-12 trunk 64689) [x86_64-darwin15]
ours: ruby 2.6.0dev (2018-09-12 leaf-insn 64688) [x86_64-darwin15]
last_commit=make opt_str_freeze leaf
Calculating -------------------------------------
trunk ours
vm2_freezestring 5.440M 31.411M i/s - 6.000M times in 1.102968s 0.191017s
Comparison:
vm2_freezestring
ours: 31410864.5 i/s
trunk: 5439865.4 i/s - 5.77x slower
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64690 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
