[inductor] Combine CppWrapperCodeGen and CppAotWrapperCodeGen (#98088)
Summary: Make CppAotWrapperCodeGen generate kernels and wrapper in one
file, which unifies the codegen for AOT and non-AOT mode. There will be
more refactoring for the AOT part.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/98088
Approved by: https://github.com/jgong5, https://github.com/jansel
