Make wrong_runtime test target independent

Author: thvnx

testsuite/tests/gnatcheck_errors/wrong_runtime/linux/test.yaml

@@ -1,5 +1,5 @@
 testsuite_driver: No output file generated by gnatcheck
-kb: info: can't find a toolchain for the following configuration: language 'Ada', target 'x86_64-linux', runtime 'unknown'
+kb: info: can't find a toolchain for the following configuration: language 'Ada', target '<target>', runtime 'unknown'
 prj.gpr:1:1: error: cannot load the Ada runtime, processing failed
 try "gnatcheck --help" for more information.
 >>>program returned status code 2

testsuite/tests/gnatcheck_errors/wrong_runtime/linux/main.adb renamed to testsuite/tests/gnatcheck_errors/wrong_runtime/main.adb

@@ -0,0 +1,9 @@
+# Expected behavior here is that libgpr warns when a runtime doesn't exist
+
+driver: gnatcheck
+project: prj.gpr
+rules:
+  - +Rrecursive_subprograms
+extra_args:
+  - --RTS=unknown
+canonicalize_target: true