capture-libs: Ignore uninteresting symbols when comparing

Some symbols appear in the dynamic symbol table as a quirk of particular
toolchains, rather than because they are literally part of the ABI.
Ignore those for the purposes of deciding whose library is newer.

Signed-off-by: Simon McVittie <smcv@collabora.com>
4 jobs for wip/t16562 in 8 minutes and 19 seconds (queued for 4 seconds)
latest
Status Job ID Name Coverage
  Test
manual #22329
allowed to fail manual
build:arch
passed #22328
build:bionic

00:07:49

passed #22327
build:buster

00:07:44

passed #22326
build:stretch

00:08:19