Facts Timeout was not settable via ansible.cfg

The timeout for gathering facts needs to be settable from three places
(highest precedence to lowest):

* programmatically
* ansible.cfg (equivalent to the user specifying it explicitly when
  calling setup)
* from the default value

The code was changed in b4bd6c80de to
allow programmatically and the default value to work correctly but
setting via ansible.cfg/parameter was broken.

This change should fix setting via ansible.cfg and adds unittests for
all three cases

Fixes #23753

lib/ansible/module_utils/facts.py

@@ -77,22 +77,24 @@ if platform.system() != 'SunOS':
 # steps do not exceed a time limit
 
 GATHER_TIMEOUT=None
+DEFAULT_GATHER_TIMEOUT = 10
 
 class TimeoutError(Exception):
     pass
 
 def timeout(seconds=None, error_message="Timer expired"):
 
-    if seconds is None:
-        seconds = globals().get('GATHER_TIMEOUT') or 10
-
     def decorator(func):
         def _handle_timeout(signum, frame):
             raise TimeoutError(error_message)
 
         def wrapper(*args, **kwargs):
+            local_seconds = seconds  # Make local var as we modify this every time it's invoked
+            if local_seconds is None:
+                local_seconds = globals().get('GATHER_TIMEOUT') or DEFAULT_GATHER_TIMEOUT
+
             signal.signal(signal.SIGALRM, _handle_timeout)
-            signal.alarm(seconds)
+            signal.alarm(local_seconds)
             try:
                 result = func(*args, **kwargs)
             finally:
@@ -103,11 +105,11 @@ def timeout(seconds=None, error_message="Timer expired"):
 
     # If we were called as @timeout, then the first parameter will be the
     # function we are to wrap instead of the number of seconds.  Detect this
-    # and correct it by setting seconds to our default value and return the
+    # and correct it by setting seconds to our sentinel value and return the
     # inner decorator function manually wrapped around the function
     if callable(seconds):
         func = seconds
-        seconds = 10
+        seconds = None
         return decorator(func)
 
     # If we were called as @timeout([...]) then python itself will take