support/testing: test_hardening disable PIC/PIE

Since [1], PIC/PIE is enabled by default but the TestRelroPartial
test expect implicitely PIC/PIE being disabled.

Disable PIC/PIE from the config fragment provided by
TestRelroPartial.

[1] 810ba387bec3c5b6904e8893fb4cb6f9d3717466

Fixes:
https://gitlab.com/buildroot.org/buildroot/-/jobs/1255661757

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

support/testing/tests/core/test_hardening.py

@@ -52,6 +52,7 @@ class TestRelroPartial(TestHardeningBase):
     config = TestHardeningBase.config + \
         """
         BR2_RELRO_PARTIAL=y
+        # BR2_PIC_PIE is not set
         """
 
     def test_run(self):