script: Improve `test-{security,symbol}-check.py` robustness

This change allows to use the `test-{security,symbol}-check.py` scripts
when building out of source tree with no need to link scripts into the
build directory.

contrib/devtools/test-security-check.py

@@ -39,7 +39,7 @@ def call_security_check(cc, source, executable, options):
         env_flags += filter(None, os.environ.get(var, '').split(' '))
 
     subprocess.run([*cc,source,'-o',executable] + env_flags + options, check=True)
-    p = subprocess.run(['./contrib/devtools/security-check.py',executable], stdout=subprocess.PIPE, universal_newlines=True)
+    p = subprocess.run([os.path.join(os.path.dirname(__file__), 'security-check.py'), executable], stdout=subprocess.PIPE, universal_newlines=True)
     return (p.returncode, p.stdout.rstrip())
 
 def get_arch(cc, source, executable):

contrib/devtools/test-symbol-check.py

@@ -23,7 +23,7 @@ def call_symbol_check(cc: List[str], source, executable, options):
         env_flags += filter(None, os.environ.get(var, '').split(' '))
 
     subprocess.run([*cc,source,'-o',executable] + env_flags + options, check=True)
-    p = subprocess.run(['./contrib/devtools/symbol-check.py',executable], stdout=subprocess.PIPE, universal_newlines=True)
+    p = subprocess.run([os.path.join(os.path.dirname(__file__), 'symbol-check.py'), executable], stdout=subprocess.PIPE, universal_newlines=True)
     os.remove(source)
     os.remove(executable)
     return (p.returncode, p.stdout.rstrip())