Improve test suite detection in run-test-suites.pl
Improve test suite detection in run-test-suites.pl

Looking for executables causes problems with leftover compiled test
suites from other branches when we forget to run make clean before
switching branches. Using the .data files is more robust as most of them
are tracked, so will be removed when switching branches.

Signed-off-by: Manuel Pégourié-Gonnard <4ba0d615aeeda88e422ca8fba28fe2938485facf@arm.com>

ARMmbed/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,Mbed-TLS/mbedtls,Mbed-TLS/mbedtls