[3.11] [3.12] gh-109972: Enhance test_gdb (GH-110026) (GH-110351)

[miss-islington]

• test_gdb failed with 15 min timeout on PPC64LE RHEL8 3.x (LTO + pydebug) #109972: Enhance test_gdb (gh-109972: Enhance test_gdb #110026)

• Split test_pycfunction.py: add test_cfunction_full.py.
  Split the function into the following 6 functions. In verbose
  mode, these "pycfunction" tests now log each tested call.

  • test_pycfunction_noargs()
  • test_pycfunction_o()
  • test_pycfunction_varargs()
  • test_pycfunction_varargs_keywords()
  • test_pycfunction_fastcall()
  • test_pycfunction_fastcall_keywords()

• Move get_gdb_repr() to PrettyPrintTests.

• Replace DebuggerTests.get_sample_script() with SAMPLE_SCRIPT.

• Rename checkout_hook_path to CHECKOUT_HOOK_PATH.

• Rename gdb_version to GDB_VERSION_TEXT.

• Replace (gdb_major_version, gdb_minor_version) with GDB_VERSION.

• run_gdb() uses "backslashreplace" error handler instead of "replace".

• Add check_gdb() function to util.py.

• Enhance support.check_cflags_pgo(): check also for sysconfig
  PGO_PROF_USE_FLAG (if available) in compiler flags.

• Move some SkipTest checks to test_gdb/init.py.

• Elaborate why gdb cannot be tested on Windows: gdb doesn't support
  PDB debug symbol files.

(cherry picked from commit 757cbd4)

• PPC64LE Fedora Stable Clang 3.x fails test_gdb #104736: Fix test_gdb tests on ppc64le with clang (gh-104736: Fix test_gdb tests on ppc64le with clang #109360)

Fix test_gdb on Python built with LLVM clang 16 on Linux ppc64le (ex:
Fedora 38). Search patterns in gdb "bt" command output to detect
when gdb fails to retrieve the traceback. For example, skip a test if
"Backtrace stopped: frame did not save the PC" is found.

(cherry picked from commit 44d9a71)

• test_gdb: test_pycfunction_fastcall_keywords() failed on PPC64LE Fedora Stable Clang 3.x #110166: Fix gdb CFunctionFullTests on ppc64le clang build (gh-110166: Fix gdb CFunctionFullTests on ppc64le clang build #110331)

CFunctionFullTests now also runs "bt" command before "py-bt-full",
similar to CFunctionTests which also runs "bt" command before
"py-bt". So test_gdb can skip the test if patterns like "?? ()" are
found in the gdb output.

(cherry picked from commit bbce8bd)

Co-authored-by: Victor Stinner vstinner@python.org
(cherry picked from commit 1de9406)