Add support for specifying the AA pipeline.

[maleadt]

Example:

@dispose ctx=Context() pb=NewPMPassBuilder() begin
    @dispose pb=NewPMPassBuilder(;debug_logging=true) mod=test_module() begin
        add!(pb, NewPMAAManager()) do aa
            add!(aa, "basic-aa")
        end
        add!(pb, "aa-eval")

        @test run!(pb, mod) === nothing
    end
end

Fixes #436
x-ref https://discourse.llvm.org/t/newpm-c-api-questions/80598

[maleadt]

Oh, it's easier, I missed https://github.com/llvm/llvm-project/blob/fd7d7882e7fa5a38d4bfde426120d4663718beb4/llvm/lib/Passes/PassBuilder.cpp#L494-L498

[maleadt]

FYI, @wsmoses, when not specifying an AA pipeline LLVM selects a default one: https://github.com/llvm/llvm-project/blob/59531cf01eb791f4cef88c2757d399eb3d90a086/llvm/lib/Passes/PassBuilderPipelines.cpp#L2192

[maleadt]

Lets wait with merging this until llvm/llvm-project#102482 lands.

[wsmoses]

oh that's nice, I am glad to be mistaken