[tests] add targets to EXECNOW commands

tests/compliance/check-json.i

 /*run.config
   NOFRAMAC:
-  EXECNOW: python3 -m json.tool < share/compliance/c11_functions.json > @DEV_NULL@
-  EXECNOW: python3 -m json.tool < share/compliance/glibc_functions.json > @DEV_NULL@
-  EXECNOW: python3 -m json.tool < share/compliance/nonstandard_identifiers.json > @DEV_NULL@
-  EXECNOW: python3 -m json.tool < share/compliance/posix_identifiers.json > @DEV_NULL@
+  EXECNOW: LOG json_@PTEST_NAME@_1.txt python3 -m json.tool < share/compliance/c11_functions.json | head -n 2 > @PTEST_RESULT@/json_@PTEST_NAME@_1.txt 2> @DEV_NULL@
+  EXECNOW: LOG json_@PTEST_NAME@_2.txt python3 -m json.tool < share/compliance/glibc_functions.json | head -n 2 > @PTEST_RESULT@/json_@PTEST_NAME@_2.txt 2> @DEV_NULL@
+  EXECNOW: LOG json_@PTEST_NAME@_3.txt python3 -m json.tool < share/compliance/nonstandard_identifiers.json | head -n 2 > @PTEST_RESULT@/json_@PTEST_NAME@_3.txt 2> @DEV_NULL@
+  EXECNOW: LOG json_@PTEST_NAME@_4.txt python3 -m json.tool < share/compliance/posix_identifiers.json | head -n 2 > @PTEST_RESULT@/json_@PTEST_NAME@_4.txt 2> @DEV_NULL@
 */

tests/compliance/oracle/json_check-json_1.txt

+{
+    "description": "C11 reserved function identifiers",

tests/compliance/oracle/json_check-json_2.txt

+{
+    "description": "Function and macro identifiers defined in the GNU C Library",

tests/compliance/oracle/json_check-json_3.txt

+{
+    "description": "Non-ISO C, Non-POSIX identifiers known to the Frama-C standard library",

tests/compliance/oracle/json_check-json_4.txt

+{
+    "description": "POSIX.1-2008 reserved function identifiers (plus a few legacy POSIX identifiers)",