Test: Disable t_cose tests in regression test suite

As now TF-M uses a fixed version of the t_cose library it is unnecessary
to execute these tests per patch as part of the regression test suite.
It is enough to enable them in test configurations that run
less frequently - such as a release test.

Change-Id: I173265516fe4806190a900e17f8f011628582691
Signed-off-by: David Vincze <david.vincze@arm.com>
1 file changed