tests: add security hardening tests for H2 and M8

tests: add security hardening tests for H2 and M8

- Add I7: /proc/dmesg root-only access test (H2)
- Add I8: /proc/cmdline root-only access test (H2)
- Add I9: /proc/PID/maps format verification test (H2)
- Add I10: /dev/random CSPRNG uniqueness test (M8)
- Update smoke_test.exp with new test patterns
- Update test_battery.exp with new test patterns

Validation:
- make test SMOKE_SMP=4: 131/131 PASS (was 127/127, +4 new tests)
- make test-battery: 157/157 PASS (was 153/153, +4 new tests)

Tests validate H2 (/proc hardening) and M8 (CSPRNG) implementations.