Skip GNU backtrace tests on 32-bit Arm

GNU backtrace() can return an empty stack on 32-bit Arm
when the build lacks suitable runtime unwind tables.
Rather than trying to infer the effective unwind-table
compiler flags in the test, skip the GNU backtrace tests
on all 32-bit Arm builds.

Author: diegorusso

Lib/test/test_frame_pointer_unwind.py

@@ -1,7 +1,6 @@
 import json
 import os
 import platform
-import shlex
 import subprocess
 import sys
 import sysconfig
@@ -105,63 +104,6 @@ def _is_arm32_build():
     return "arm" in abi
 
 
-def _cflags_have_unwind_tables(cflags):
-    unwind_tables = False
-    asynchronous_unwind_tables = False
-    exceptions = False
-
-    try:
-        options = shlex.split(cflags)
-    except ValueError:
-        options = cflags.split()
-
-    for option in options:
-        if option == "-funwind-tables":
-            unwind_tables = True
-        elif option == "-fno-unwind-tables":
-            unwind_tables = False
-        elif option == "-fasynchronous-unwind-tables":
-            asynchronous_unwind_tables = True
-        elif option == "-fno-asynchronous-unwind-tables":
-            asynchronous_unwind_tables = False
-        elif option == "-fexceptions":
-            exceptions = True
-        elif option == "-fno-exceptions":
-            exceptions = False
-
-    return unwind_tables or asynchronous_unwind_tables or exceptions
-
-
-def _build_has_unwind_tables():
-    cflags = [
-        value for value in (
-            sysconfig.get_config_var("PY_CORE_CFLAGS"),
-            sysconfig.get_config_var("PY_STDMODULE_CFLAGS"),
-        )
-        if value
-    ]
-    if not cflags:
-        cflags = [
-            value for value in (
-                sysconfig.get_config_var("PY_CFLAGS"),
-                sysconfig.get_config_var("CFLAGS"),
-            )
-            if value
-        ]
-
-    return (
-        bool(cflags)
-        and all(_cflags_have_unwind_tables(value) for value in cflags)
-    )
-
-
-def _gnu_backtrace_requires_unwind_tables():
-    if not _is_arm32_build():
-        return False
-
-    return not _build_has_unwind_tables()
-
-
 def _build_stack_and_unwind(unwinder):
     import operator
 
@@ -369,8 +311,8 @@ def test_manual_unwind_respects_frame_pointers(self):
 @unittest.skipIf(support.is_wasi, "test not supported on WASI")
 @unittest.skipUnless(sys.platform == "linux", "GNU backtrace unwinding test requires Linux")
 @unittest.skipIf(
-    _gnu_backtrace_requires_unwind_tables(),
-    "GNU backtrace unwinding on Arm 32-bit requires unwind tables",
+    _is_arm32_build(),
+    "GNU backtrace unwinding skipped on Arm 32-bit",
 )
 class GnuBacktraceUnwindTests(unittest.TestCase):