Add test for issue #1229

[VirxEC]

Issue #1229 <-

Turns out it can be in one file and doesn't have to be in different ones so it made writing the test a bit easier.

Fails building with (abridged):

gen2.cxx:(.text.cxxbridge1$new_autocxx_autocxx_wrapper+0x0): multiple definition of `cxxbridge1$new_autocxx_autocxx_wrapper'; /tmp/.tmpfDPHVE/libautocxx-demo.a(gen0.o):gen0.cxx:(.text.cxxbridge1$new_autocxx_autocxx_wrapper+0x0): first defined here

[adetaylor]

Thanks for this! Assuming it reproduces the problem, this will indeed make it easier for me to figure out what names we're not unique-ifying properly. I'm traveling next week so it might take me a little while to get to it, but I will.