[clang-tools-extra] [Clang-Tidy] Handle nested-name-specifier in "llvm-prefer-isa-or-dyn-cast-in-conditionals" (PR #155982)

[via cfe-commits]

================
@@ -76,6 +136,16 @@ bool foo(Y *y, Z *z) {
   // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: isa_and_nonnull<> is preferred
   // CHECK-FIXES: if (isa_and_nonnull<Y>(z->bar()))
 
+  if (z->bar() && cast_or_null<Y>(z->bar()))
+    return true;
+  // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: isa_and_nonnull<> is preferred
+  // CHECK-FIXES: if (isa_and_nonnull<Y>(z->bar()))
+
+  if (z->bar() && cast_if_present<Y>(z->bar()))
+    return true;
+  // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: isa_and_nonnull<> is preferred
+  // CHECK-FIXES: if (isa_and_nonnull<Y>(z->bar()))
----------------
flovent wrote:

>  Keep _present and _or_null as written.

I think that's reasonable, keeping their original style.

> Replace x && isa<Y>(x) with what configuration files choose (isa_and_nonnull or isa_and_present).

What default option should we use here, i think we don't have cast APIs with `present` postfix when this check was added to clang-tidy.

https://github.com/llvm/llvm-project/pull/155982