TestEmptyDwarfRanges has been added in CL 94816.
This test is failing on Plan 9 because executables
don't have a DWARF symbol table.

Fixes #24226.

Change-Id: Iff7e34b8c2703a2f19ee8087a4d64d0bb98496cd
Reviewed-on: https://go-review.googlesource.com/98275Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>