AT_SYSINFO_EHDR may be defined even if no vdso is used. e.g. 32-bit ARM
processes have a vdso on 64-bit ARM cpus, but not on 32-bit cpus.
Change-Id: I4d9ce029bb47efc33ea16cb4c5c2055c1b9330c9
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/1860935
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Joshua Peraza <jperaza@chromium.org>