[clang] [NFC] [Sema] [Modules] Use DynamicRecursiveASTVisitor to reduce generted code size (PR #151074)

[Nikita Popov via cfe-commits]

nikic wrote:

> From [1b4db78](https://github.com/llvm/llvm-project/commit/1b4db78d2eaa070b3f364a2d2b2b826a5439b892) . But I didn't use `function_ref` as it seems not safe to store functions.

You can probably use unique_function instead.

https://github.com/llvm/llvm-project/pull/151074