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
diff --git a/build_helper/build_helper_configs.py b/build_helper/build_helper_configs.py
index 4d7f4e4..fe7d80b 100755
--- a/build_helper/build_helper_configs.py
+++ b/build_helper/build_helper_configs.py
@@ -805,7 +805,7 @@
                 "tfm_platform":     ["arm/corstone1000"],
                 "compiler":         ["GCC_10_3"],
                 "isolation_level":  ["1"],
-                "test_regression":  ["RegBL2, RegS"],
+                "test_regression":  ["RegS"],
                 "test_psa_api":     ["OFF"],
                 "cmake_build_type": ["Debug"],
                 "with_bl2":         [True],