Add (e)z80-clang compilers. (#7546)

These clang + LLVM backends are not upstreamed but [a community
effort](https://github.com/CE-Programming/llvm-project/), so it's a bit
customized.

This requires https://github.com/compiler-explorer/infra/pull/1566

_Edit: tested locally, works fine._

types/instructionsets.ts

@@ -35,6 +35,7 @@ export const InstructionSetsList = [
     'ebpf',
     'evm',
     'eravm',
+    'ez80',
     'hook',
     'core',
     'java',
@@ -61,6 +62,7 @@ export const InstructionSetsList = [
     'wasm64',
     'wdc65c816',
     'xtensa',
+    'z180',
     'z80',
 ] as const;