gh-127119: Faster check for small ints in long_dealloc (GH-127620)

Tools/gdb/libpython.py

@@ -890,7 +890,7 @@ class PyLongObjectPtr(PyObjectPtr):
 
     def proxyval(self, visited):
         '''
-        Python's Include/longinterpr.h has this declaration:
+        Python's Include/cpython/longinterpr.h has this declaration:
 
             typedef struct _PyLongValue {
                 uintptr_t lv_tag; /* Number of digits, sign and flags */
@@ -909,8 +909,7 @@ class PyLongObjectPtr(PyObjectPtr):
                 - 0: Positive
                 - 1: Zero
                 - 2: Negative
-            The third lowest bit of lv_tag is reserved for an immortality flag, but is
-            not currently used.
+            The third lowest bit of lv_tag is set to 1 for the small ints and 0 otherwise.
 
         where SHIFT can be either:
             #define PyLong_SHIFT        30