Don't use insn_return inside gcd.
Don't use insn_return inside gcd.

When build_gcd() is used to build an XSUB version, it is not correct to
use return instruction - we need to push the value into perl stack
instead.

vickenty/loljit,vickenty/libjit-perl,vickenty/loljit,vickenty/libjit-perl,vickenty/libjit-perl,vickenty/libjit-perl,vickenty/libjit-perl,vickenty/loljit,vickenty/loljit