Search for files types only when capturing results.

Fixes issue where we were matching a .xml directory.

Change-Id: I16750ec1abce1d1c80fe83ac01be14a57403d43c
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/c/dsg-gnu/Internal/gnu-devtools-for-arm/+/714577


Tested-by: Daniel Fellows <daniel.fellows@arm.com>
Tested-by: Service account - used by users in DSG GNU team <dgboter@arm.com>
Reviewed-by: Vaseeharan Vinayagamoorthy <vaseeharan.vinayagamoorthy@arm.com>
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/c/dsg-gnu/Internal/gnu-devtools-for-arm/+/717889


Reviewed-by: Daniel Fellows <daniel.fellows@arm.com>