[lldb][ARM/AArch64] Update dissembler to v9.3-a

[DavidSpickett]

Summary

This means sve2 is enabled by default and the v8.8 mops (memcpy
and memset acceleration instructions) and HBC (hinted conditional
branch) extensions can be disassembled.

v9.3-a is equivalent to v8.8-a except that in v9.0-a sve2 was
enabled by default so v9.3-a includes that too.

MTE remains an optional extension, only enabled for specific CPUs.

lldb/source/Plugins/Disassembler/LLVMC/DisassemblerLLVMC.cpp

DisassemblerLLVMC::DisassemblerLLVMC(const ArchSpec &arch,
   ArchSpec thumb_arch(arch);
   if (triple.getArch() == llvm::Triple::arm) {
     std::string thumb_arch_name(thumb_arch.GetTriple().getArchName().str());
     // Replace "arm" with "thumb" so we get all thumb variants correct
     if (thumb_arch_name.size() > 3) {
       thumb_arch_name.erase(0, 3);
       thumb_arch_name.insert(0, "thumb");
     } else {
-      thumb_arch_name = "thumbv8.7a";
+      thumb_arch_name = "thumbv9.3a";
     }
     thumb_arch.GetTriple().setArchName(llvm::StringRef(thumb_arch_name));
   }
 
   // If no sub architecture specified then use the most recent arm architecture
-  // so the disassembler will return all instruction. Without it we will see a
-  // lot of unknow opcode in case the code uses instructions which are not
-  // available in the oldest arm version (used when no sub architecture is
-  // specified)
+  // so the disassembler will return all instructions. Without it we will see a
+  // lot of unknown opcodes if the code uses instructions which are not
+  // available in the oldest arm version (which is used when no sub architecture
+  // is specified).
   if (triple.getArch() == llvm::Triple::arm &&
       triple.getSubArch() == llvm::Triple::NoSubArch)
-    triple.setArchName("armv8.7a");
+    triple.setArchName("armv9.3a");
 
   std::string features_str;
   const char *triple_str = triple.getTriple().c_str();
 
   // ARM Cortex M0-M7 devices only execute thumb instructions
   if (arch.IsAlwaysThumbInstructions()) {
     triple_str = thumb_arch.GetTriple().getTriple().c_str();
     features_str += "+fp-armv8,";
if (arch_flags & ArchSpec::eMIPSAse_msa)
       features_str += "+msa,";
     if (arch_flags & ArchSpec::eMIPSAse_dsp)
       features_str += "+dsp,";
     if (arch_flags & ArchSpec::eMIPSAse_dspr2)
       features_str += "+dspr2,";
   }
 
   // If any AArch64 variant, enable latest ISA with any optional
-  // extensions like SVE.
+  // extensions like MTE.
   if (triple.isAArch64()) {
-    features_str += "+v8.7a,+sve2,+mte";
+    features_str += "+v9.3a,+mte";
 
     if (triple.getVendor() == llvm::Triple::Apple)
       cpu = "apple-latest";
   }
 
   // We use m_disasm_up.get() to tell whether we are valid or not, so if this
   // isn't good for some reason, we won't be valid and FindPlugin will fail and
   // we won't get used.