Fix detection of gdb built without Python scripting support.
* check_usable_gdb() doesn't check gdb exit code when calling
run_gdb().
* Use shutil.which() to get the path to the gdb program.
* 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.
Split test_gdb.py file into a test_gdb package made of multiple
tests, so tests can now be run in parallel.
* Create Lib/test/test_gdb/ directory.
* Split test_gdb.py into multiple files in Lib/test/test_gdb/
directory.
* Move Lib/test/gdb_sample.py to Lib/test/test_gdb/ directory.
Update get_sample_script(): use __file__ to locate gdb_sample.py.
* Move gdb_has_frame_select() and HAS_PYUP_PYDOWN to test_misc.py.
* Explicitly skip test_gdb on Windows. Previously, test_gdb was
skipped even if gdb was available because of
gdb_has_frame_select().
Victor Stinner