PR148 again: don't defuse IF_LCMPxx

PR148 again: don't defuse IF_LCMPxx
* src/vm/jit/stack.c: Unconditionally use BUILTIN_lcmp, as no
architecture implements it.
* src/vm/jit/builtin.cpp: Likewise
* src/vm/jit/builtintable.inc: Copied BUILTIN_lcmp entry (from
automatic table to internal table).
* src/vm/jit/alpha/arch.h: Re-enable SUPPORT_LONG_CMP.
* src/vm/jit/arm/arch.h,
* src/vm/jit/i386/arch.h,
* src/vm/jit/mips/arch.h,
* src/vm/jit/powerpc/arch.h,
* src/vm/jit/powerpc64/arch.h,
* src/vm/jit/s390/arch.h,
* src/vm/jit/x86_64/arch.h: Likewise.