Build: Update CS1K build configs

Following changes are made for CS1K build configs:
1. Add corstone1000_GCC_2_RegS_Debug_BL2_NSOFF_CS1K_TEST_FVP config into
   per-patch test config.
2. Cover Isolation Level 2 on CS1K in nightly and release test jobs.

Signed-off-by: Xinyu Zhang <xinyu.zhang@arm.com>
Change-Id: I3a7fceda5dd6df2e867d69365735396d8dd02fc9
1 file changed