* src/vm/jit/code.c (code_get_stack_frame_size): Deal with 4/8-byte

* src/vm/jit/code.c (code_get_stack_frame_size): Deal with 4/8-byte
stackslots.

* src/vm/jit/tools/genoffsets.c (main): Offsets of intregs and fltregs.

* src/vm/jit/i386/asmpart.S (asm_replacement_out): Renamed regs to
intregs. Some cleanup.

* src/vm/jit/replace.c (replace_activate_replacement_point)
(replace_deactivate_replacement_point): Enabled on x86_64.
(replace_read_executionstate, replace_write_executionstate):
Deal with 4/8-byte stackslots. Handle float registers.
(replace_executionstate_println, replace_sourcestate_println):
Print register names where possible.

* src/vm/jit/x86_64/md.c (md_patch_replacement_point): Added.
(vim boilerplate): Added.

* src/vm/jit/x86_64/codegen.c (codegen): Handle replacement points.
Generate replacement-out stubs.

* src/vm/jit/x86_64/asmpart.S (asm_replacement_out, asm_replacement_in):
Added.
(vim boilerplate): Added.

* src/vm/jit/replace.h (executionstate): Separate registers into int
and float registers. Some cleanup, use INT_REG_CNT, FLT_REG_CNT macros.