Add vendor_executes_system_violators attribute

Temporary attribute (checked against in CTS) to point out vendor
processes that run /system executables. These are currently only down to
2-3 of them that are related to telephony on sailfish

Bug: 36463595
Test: Build succeeds for sailfish
Test: ./cts-tradefed run cts -m CtsSecurityHostTestCases -t \
          android.security.cts.SELinuxHostTest#testNoExemptionsForVendorExecutingCore \
          --skip-device-info --skip-preconditions --skip-connectivity-check \
          --abi arm64-v8a

Change-Id: I9eb40ad259aefba73869d6a1b40186d33fa475dd
Signed-off-by: Sandeep Patil <sspatil@google.com>