it is dangerous idea, I would recommend you not to proceed.
If you relocate forcefully from C:\Program Files (x86) to C:\Program Files, you may face errors because system will not find elements in the right place, because, whatever you do, every attempt from a 32 bits to C:\Program Files will be redirected to C:\Program Files (x86).
It may cause plugin not to be there, help file not to responds, icons to get missing or whatever.
No idea if that can be controlled by a Registry key, but I would not even try to change it, waaaaaaay to risky. You could break others things.
We do not have the issue here. We do not install in Program Files.
PLSQL Dev is on C:\PLSQLDeveloper or C:\PLSQLDeveloper64 depending the architecture. Not in any Windows controlled space. So a lot safer.