`add_ptr` has bad `:nothrow` effects

[adienes]

it appears the changes in #53687 caused

julia> Base.infer_effects(+, Tuple{Ptr{UInt8}, UInt})
(+c,+e,!n,+t,+s,+m,+u,+o,+r)

I'm assuming this is a bug as I don't know how that call could throw --- and it does not match the effects on previous versions.

adding @_nothrow_meta to +(x::Ptr, y::Integer) and -(x::Ptr, y::Integer) should fix the symptom for +, but I'm assuming it'd be desirable to fix the intrinsic as well

[vtjnash]

It looks like it changed some of the implementation without updating the nothrow modeling here:

julia/base/compiler/tfuncs.jl

Lines 2893 to 2894 in 66dc4d2

	# The remaining intrinsics are math/bits/comparison intrinsics. They work on all
	# primitive types of the same type.

(I was looking earlier today finding a lot of bugs here and started https://github.com/JuliaLang/julia/pull/new/jn/builtin-effects-free to fix some of them)