[CodeGen][GC] Remove `GCInfoPrinter` (#75033)

This pass is broken and looks like no one uses it for the last 15+ years.

```c++
bool Printer::runOnFunction(Function &F) {
  if (F.hasGC())
    return false;

  GCFunctionInfo *FD = &getAnalysis<GCModuleInfo>().getFunctionInfo(F);
```
```c++
GCFunctionInfo &GCModuleInfo::getFunctionInfo(const Function &F) {
  assert(!F.isDeclaration() && "Can only get GCFunctionInfo for a definition!");
  assert(F.hasGC()); // Equivalent to `assert(false);` when called by `Printer::runOnFunction`
```

See also #74972.