* Fix closures using FFI_REGISTER ABI
ffi_closure_REGISTER had the positions of the closure and return address
switched, resulting in a segfault when calling a closure created with
the FFI_REGISTER ABI.
* Fix comment and remove redundant assembly
* After fixing closures using FFI_REGISTER ABI, the comments were
incorrect, not reflecting the value that was actually loaded into eax
and ecx.
* Additionally, ecx was loaded with the data at esp + closure_FS only
to write it back to esp + closure_FS. Both commands were removed as
they end up not having any effect as ecx is overwritten during
FFI_CLOSURE_COPY_TRAMP_DATA.
2263d6037f