Build: Turn off TEST_BL2 & TEST_S_PS for corstone1000

With the new changes on corstone1000, we don't have enough RAM to run
both TEST_BL2 and TEST_S_PS. Turning off these tests so that corstone1000 can
build the tfm test configuration in the CI.

Signed-off-by: Emekcan Aras <emekcan.aras@arm.com>
Change-Id: I441336e3b8f34b21b4e139202a94bae5fa896ee1
2 files changed