[llvm] [AMDGPU][MC] Allow UC_VERSION_* constant reuse (PR #96461)

[Carl Ritson via llvm-commits]

perlfu wrote:

> > This might be difficult. The main issue we are seeing right now is a tool that ends up initializing multiple disassembler instance on the same context. We can probably replicate this in a unit test if necessary.
> 
> Wouldn't this be just .set UC_VERSION_something something in an assembler file?

Using the .set directive in an assembly file only tests the assembly override of the symbol.
The issue that need solving is multiple disassemblers in the same MCContext.

I've added an assembly override test and unit tests that cover the use of multiple diassemblers in the same context as well as UC_VERSION overrides.
This involved fixing up the code to use an UC_VERSION overrides.



https://github.com/llvm/llvm-project/pull/96461