CPU/Recompiler: Prevent vixl from using scratch registers

This took too long to find that it was trashing one of our register
cache values. Let it abort instead, until we use the base assembler
instead of the macro assembler.

src/core/cpu_recompiler_code_generator_aarch64.cpp

@@ -86,6 +86,12 @@ CodeGenerator::CodeGenerator(Core* cpu, JitCodeBuffer* code_buffer, const ASMFun
                   a64::PositionDependentCode),
     m_emit(&m_near_emitter)
 {
+  // remove the temporaries from vixl's list to prevent it from using them.
+  // eventually we won't use the macro assembler and this won't be a problem...
+  m_near_emitter.GetScratchRegisterList()->Remove(16);
+  m_near_emitter.GetScratchRegisterList()->Remove(17);
+  m_far_emitter.GetScratchRegisterList()->Remove(16);
+  m_far_emitter.GetScratchRegisterList()->Remove(17);
   InitHostRegs();
 }