When tests are run with a wildcard filter on the backend, e.g.
"TEST/ES2_Vulkan*" the same tests from different backends may
end up in the same trace file directory, e.g. TEST_ES2_Vulkan
and TEST_ES2_Vulkan_SwiftShader. So far, when searching for the
ES2_Vulkan trace files the check for trace files would them also
pick up all the _SwiftShader files, and the skript would assume
that the file count is wrong and skip the replay.

By adding "_capture" the start of the commonly used suffix, this
is avoided and replays are no longer skipped because mis-counting
capture files.

Bug: angleproject:5972
Change-Id: I7af54aaf51ee7070333ffe81974d866bd89dbd6f
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2897236
Commit-Queue: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Cody Northrop <cnorthrop@google.com>