[PredicateInfo] Reformat PT_Switch's annotation as valid comments (llvm#165249)

Previously, PredicateInfo brutally annotated `PT_Switch` as follows:
```python
f'"; switch predicate info ... CaseValue: ... Switch: {*PS->Switch} Edge: ... RenamedOp: ..."'
```

However, the `switch` instruction in LLVM might cross >1 lines, leading
to the annotation of `PT_Switch` being **illegal comments**, e.g.,
```LLVM
; switch predicate info { CaseValue: i32 1 Switch:  switch i32 %x, label %default [
    i32 0, label %case0
    i32 1, label %case1
    i32 2, label %case0
    i32 3, label %case3
    i32 4, label %default
  ] Edge: [label %sw,label %case1], RenamedOp: %x }
  x.0 = bitcast i32 %x to i32
```

This patch removes the `switch` printing, reformating the `PT_Switch`'s
annotation as follows:
```python
f'"; switch predicate info ... CaseValue: ... Edge: ...  RenamedOp: ..."'
```
, e.g., 

```LLVM
; switch predicate info { CaseValue: i32 1 Edge: [label %sw,label %case1], RenamedOp: %x }
  x.0 = bitcast i32 %x to i32
```

It should be Okay because `CaseValue: ...` + `Edge: ...` are meaningful
enough for diagnostics, covering the necessary info provided by full
switch printing (E.g., `PT_Branch` also did not print the relevant
branch instruction).

Author: Camsyn

llvm/lib/Transforms/Utils/PredicateInfo.cpp

@@ -819,7 +819,7 @@ class PredicateInfoAnnotatedWriter : public AssemblyAnnotationWriter {
         OS << "]";
       } else if (const auto *PS = dyn_cast<PredicateSwitch>(PI)) {
         OS << "; switch predicate info { CaseValue: " << *PS->CaseValue
-           << " Switch:" << *PS->Switch << " Edge: [";
+           << " Edge: [";
         PS->From->printAsOperand(OS);
         OS << ",";
         PS->To->printAsOperand(OS);

llvm/test/Transforms/Util/PredicateInfo/condprop.ll

@@ -133,19 +133,13 @@ define void @test4(i1 %b, i32 %x) {
 ; CHECK-LABEL: @test4(
 ; CHECK-NEXT:    br i1 [[B:%.*]], label [[SW:%.*]], label [[CASE3:%.*]]
 ; CHECK:       sw:
-; CHECK:         i32 0, label [[CASE0:%.*]]
-; CHECK-NEXT:    i32 1, label [[CASE1:%.*]]
-; CHECK-NEXT:    i32 2, label [[CASE0]]
-; CHECK-NEXT:    i32 3, label [[CASE3]]
-; CHECK-NEXT:    i32 4, label [[DEFAULT:%.*]]
-; CHECK-NEXT:    ] Edge: [label [[SW]],label %case1], RenamedOp: [[X:%.*]] }
-; CHECK-NEXT:    [[X_0:%.*]] = bitcast i32 [[X]] to i32
-; CHECK-NEXT:    switch i32 [[X]], label [[DEFAULT]] [
-; CHECK-NEXT:    i32 0, label [[CASE0]]
-; CHECK-NEXT:    i32 1, label [[CASE1]]
-; CHECK-NEXT:    i32 2, label [[CASE0]]
-; CHECK-NEXT:    i32 3, label [[CASE3]]
-; CHECK-NEXT:    i32 4, label [[DEFAULT]]
+; CHECK:         [[X_0:%.*]] = bitcast i32 [[X:%.*]] to i32
+; CHECK-NEXT:    switch i32 [[X]], label [[DEFAULT:%.*]] [
+; CHECK-NEXT:      i32 0, label [[CASE0:%.*]]
+; CHECK-NEXT:      i32 1, label [[CASE1:%.*]]
+; CHECK-NEXT:      i32 2, label [[CASE0]]
+; CHECK-NEXT:      i32 3, label [[CASE3]]
+; CHECK-NEXT:      i32 4, label [[DEFAULT]]
 ; CHECK-NEXT:    ]
 ; CHECK:       default:
 ; CHECK-NEXT:    call void @bar(i32 [[X]])