When all Python shell tests run concurrently during 'perf test' under
heavy load:
1. Unfiltered 'perf list' initializes all hardware PMUs and metrics in
   each test process; use 'perf list tracepoint' when checking for
   tracepoint events.
2. Running 'perf record' without '-B -N --no-bpf-event' synthesizes BPF
   events across the system and caches build-ids into ~/.debug; add
   '-B -N --no-bpf-event' to all Python shell test recordings.
3. Drop '-a' in test_check_perf_trace_python.sh,
   test_rw_by_file_python.sh, test_rw_by_pid_python.sh,
   test_rwtop_python.sh, and test_syscall_counts_by_pid_python.sh where
   only a single child workload ('dd' or 'sleep') is tested, avoiding
   system-wide /proc synthesis and ringbuffer contention.
4. Add '-W 1' to 'ping -c 1' in test_net_dropmonitor_python.sh and
   test_netdev_times_python.sh, and narrow 'compaction:*' to
   'compaction:mm_compaction_begin,compaction:mm_compaction_end' in
   test_compaction_times_python.sh.

Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Refactor 'perf script' to launch standalone scripts directly via fork()
and execvp() and remove the legacy embedded Perl and Python scripting
engines:
- Remove the embedded Perl scripting engine
  (util/scripting-engines/trace-event-perl.c), Perl scripts, bin
  wrappers, and Trace-Util library
  (scripts/perl/Perf-Trace-Util/), and script_perl.sh test.
- Remove libperl feature checks from Makefile.config, Makefile.perf,
  builtin-check.c, and Documentation/perf-check.txt.
- Remove -g / --gen-script option and scripting_ops dispatch table from
  builtin-script.c and trace-event-scripting.c.
- Hide the legacy -s / --script option and update script discovery in
  find_script() and list_available_scripts() to prioritize the system
  'python' directory over bare filenames in the current directory.
- Update the Python script shell tests (test_arm_coresight_disasm.sh,
  test_task_analyzer.sh, and test_*_python.sh) to invoke scripts via
  'perf script <script>' rather than running the Python interpreter
  directly on the script file path.

Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Port stackcollapse.py from tools/perf/scripts/python/ to a standalone
script in tools/perf/python/ refactored into a StackCollapseAnalyzer
class.

Improvements compared to the legacy script:
- Traverse sample.callchain directly from perf.session without
  allocating per-event dictionaries, and fall back to sample.symbol when
  a sample has no callchain.
- Replace deprecated optparse with argparse, adding -i/--input alongside
  --include-tid, --include-pid, --no-comm, --tidy-java, and --kernel.
- Handle BrokenPipeError cleanly when output is piped into downstream
  tools (such as head or flamegraph.pl).

Add a shell test (test_stackcollapse_python.sh) using a CPU workload
(perf test -w noploop) to verify the standalone script.

Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>