LoadConstant refactors broke code caching

[neobrain]

Since #5139 was merged, code cache validation fails on even the simplest programs (e.g. ls). main had already been failing without the patch from #5226, but #5139 added further divergence on top of that.

To reproduce:

• Check out 0a18ea8 and apply JIT: Ensure code cache consistency by zero-initializing padding bytes #5226 on top of it. Observe that code cache validation passes
• Check out d582356 and apply JIT: Ensure code cache consistency by zero-initializing padding bytes #5226 on top of it. Observe that code cache validation fails

@Sonicadvance1 Could you take a look at this? It's blocking me from properly rebasing the remaining code caching patches. I'm already bottlenecked by catching up on work that happened during Christmas holidays, so would appreciate not chasing down unrelated rabbit holes in the meantime (while rebasing on and checking the other patches that accumulated).

[Sonicadvance1]

$ git log --oneline
146f36fda (HEAD) JIT: Ensure code cache consistency by zero-initializing padding bytes
0a18ea8f4 Merge pull request #5138 from bylaws/eCcodecachingrelocval

Your code cache validation doesn't work for me regardless.

$ ./Bin/FEX `which ls` /
Illegal instruction        (core dumped) ./Bin/FEX `which ls` /

A 2135621|2135621 203.598 Cache validation failed at offset 0x0: f0030000 <-> 30040000 (at 0xaaaae0d3f000 <-> 0xaaaae3264000, guest block 0x1000)

[neobrain]

Can you try with the default configuration as saved by FEXConfig?

[Sonicadvance1]

ryanh@orion-o6:~/.fex-emu$ cat Config.json
{"Config":{"OutputLog":"server", "SilentLog":"0","RootFS":"Ubuntu_24_04"}}

ryanh@orion-o6:/mnt/Work/Work/work/FEXNew/Build_Radxa$ ./Bin/FEX `which ls` /
bin  boot  dev  efi  etc  home  lib  lost+found  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var
ryanh@orion-o6:/mnt/Work/Work/work/FEXNew/Build_Radxa$ ./Bin/FEX `which ls` /
Illegal instruction        (core dumped) ./Bin/FEX `which ls` /
ryanh@orion-o6:/mnt/Work/Work/work/FEXNew/Build_Radxa$ ./Bin/FEXGetConfig --version
FEX-2512-80-g43fc263

A 2168217|2168217 0.887 Cache validation failed at offset 0x0: f0030000 <-> 30040000 (at 0xaaaaff03e000 <-> 0xaaab1255e000, guest block 0x1000)

$ git log --oneline
43fc263a6 (HEAD) JIT: Ensure code cache consistency by zero-initializing padding bytes
0a18ea8f4 Merge pull request #5138 from bylaws/eCcodecachingrelocval