`@turbo` slightly broken on 1.12

on nightly, the following code
```
using LoopVectorization
function f()
B = zeros(3)
@turbo B .+ 1
B
end
f()
```
produces
```
ERROR: LoadError: TypeError: in typeassert, expected Expr, got a value of type GlobalRef
Stacktrace:
[1] substitute_broadcast(q::Expr, mod::Symbol, inline::Bool, u₁::Int8, u₂::Int8, v::Int8, threads::Int64, warncheckarg::Int64, safe::Bool)
@ LoopVectorization ~/.julia/dev/LoopVectorization/src/constructors.jl:70
[2] turbo_macro(::Module, ::LineNumberNode, ::Expr)
@ LoopVectorization ~/.julia/dev/LoopVectorization/src/constructors.jl:295
[3] var"@turbo"(__source__::LineNumberNode, __module__::Module, args::Vararg{Any})
@ LoopVectorization ~/.julia/dev/LoopVectorization/src/constructors.jl:404
[4] include(mod::Module, _path::String)
@ Base ./Base.jl:300
[5] exec_options(opts::Base.JLOptions)
@ Base ./client.jl:329
[6] _start()
@ Base ./client.jl:558
in expression starting at /home/oscardssmith/.julia/dev/LoopVectorization/test.jl:6
```
rather than working as expected. This seems to be a consequence of https://github.com/JuliaLang/julia/pull/56746