support/testing: fix hardening tests

support/testing: fix hardening tests

Since "2467822c85 package/checksec: bump to version 2.1.0" the hardening
tests fail because upstream slightly changed the way the script is
called.
According to README.md: "- All options now require `--$option=$value`
instead of `--$option $value`"

Instead of just replacing '--output json' with '--output=json' take into
account that upstream also changed the usage example to show --format
instead of --output. Both options do exactly the same, but following the
usage example seems to be more future-proof.

Upstream also improved the json output. Now when a file is passed as
parameter, the json has the file name as the main key, instead of the
string "file". Adjust the test cases accordingly.

Fixes:
tests.core.test_hardening.TestFortifyConserv
tests.core.test_hardening.TestFortifyNone
tests.core.test_hardening.TestRelro
tests.core.test_hardening.TestRelroPartial
tests.core.test_hardening.TestSspNone
tests.core.test_hardening.TestSspStrong

Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Cc: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Cc: Matt Weber <matthew.weber@rockwellcollins.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Reviewed-by: Matt Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>