Fix isolated dlopen

[fingolfin]

In locate, when launching an external Julia to test whether dlopen work
on a library, pass --startup-file=no to the subprocess to avoid any issues
with commands in a user's startup.jl file.

Fixes #194

On master, this was already fixed by PR #189 -- if you prefer, I can also turn this into a cherry-pick of 81f03da

It would be great if a new release of BinaryProvider.jl with this fix could be made soon. Perhaps first wait if others can reproduce the issue and the fix. For me, the culprit was this:

$ cat .julia/config/startup.jl
using InteractiveUtils
if isdefined(InteractiveUtils, :define_editor)
    InteractiveUtils.define_editor("bbedit") do cmd, path, line
       `$cmd $path:$line`
    end
end

See also JuliaPackaging/BinaryBuilder.jl#793

[giordano]

As I wrote in the PR to BinaryBuilder, I think the change the good anyway, but before declaring #194 closed I'd like to hear from other people experiencing the same issue if this indeed fixes it for them.

[giordano]

Ok, I'm going to merge this and tag a new version because the change is good, but I'm keeping #194 open for the time being.