[llvm] [llvm][AArch64][TableGen] Create a ProcessorAlias record. NFC (PR #96249)

[Tomas Matheson via llvm-commits]

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@@ -221,8 +221,28 @@ static void EmitARMTargetDef(RecordKeeper &RK, raw_ostream &OS) {
   OS << "#ifdef EMIT_CPU_INFO\n"
      << "inline constexpr CpuInfo CpuInfos[] = {\n";
 
+  std::map<std::string, std::pair<std::string, const Record *>> ProcessorModels;
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tmatheson-arm wrote:

You don't really use the `std::string Alias` for anything but a comment, this could be
```cpp
 std::map<std::string, const Record *> ProcessorModels;
```
which is easier to understand.

https://github.com/llvm/llvm-project/pull/96249