[lld] Delete lto-late-arm.ll

This test is failing on a couple of bots and on premerge after
a082f66.

That patch configures the relevant libcalls for ARM in RuntimeLibCalls.
This causes __rt_sdiv to get pulled into the LTO preopt IR. This should
happen for other builtins as well, which means that the original issue
that the patch introducing this patch intended to diagnose should no
longer exist.

The compiler generated calls to builtins mentioned in
7f9a004 should always have definitions,
assuming they are available in the link and will not only get pulled in
late if lazily loading symbols from archives. We otherwise get the
standard diagnostic if they are not.

Author: boomanaiden154