[clang] [analyzer] Turn NodeBuilderContext into a class (PR #84638)

[Diego A. Estrada Rivera via cfe-commits]

================
@@ -194,11 +194,12 @@ class CoreEngine {
 };
 
 // TODO: Turn into a class.
----------------
diego-est wrote:

Done.

https://github.com/llvm/llvm-project/pull/84638