Remove manual tests from tests-standard.mk

These tests require build variables to be set to non-default values
(USE_NVM=1 and NEW_TEST_SESSION=0). This conflicts with other tests that
are part of tests-standard (the default set of tests) and so the
proposed solution is to remove them from this set.

Change-Id: Id54148aab9410002dace33ad595ac1b0cf4678ca
Signed-off-by: Paul Beesley <paul.beesley@arm.com>