[llvm] [SystemZ] Expand and automate .insn directive coverage (PR #222031)

[Dominik Steenken via llvm-commits]

================
@@ -188,28 +192,28 @@ def getTwoOperandOpcode : InstrMapping {
 class InstE<bits<16> op, dag outs, dag ins, string asmstr, list<dag> pattern>
   : InstSystemZ<2, outs, ins, asmstr, pattern> {
   field bits<16> Inst;
-
-  let Inst = op;
+  bits<16> enc;
----------------
dominik-steenken wrote:

Done. The consistent format rule is now
```
Full-width fields
<space>
Partial-width fields
<space>
Encoding let-bindings
<space>
Flag let-bindings
```

https://github.com/llvm/llvm-project/pull/222031