10: Warn for listcomp r=ltratt a=nanjekyejoannah

Warnings for list comprehension, which include:
- explicit tuple/parentheses for list items
- leaking iterator variable.

Co-authored-by: Joannah Nanjekye <jnanjekye@python.org>

Closes python/miss-islington#9

Co-authored-by: Jules <57632293+JuliaPoo@users.noreply.github.com>

Update sys module to conform with the PEP, add matching C API

Per docs/tier8-class-b-cport-migrate-arm-spec.md theologian 01:01:50Z +
supervisor 01:02:46Z ADOPTED + supervisor 01:18:35Z + 03:44:19Z +
04:14:27Z (8-incident root-cause attribution to §3.5 restore-trap +
b83f084 fix LIVE).

Migrates HIRBuilder std::vector<ExceptionTableEntry> exception_table_
field to PhxExceptionTable (purpose-built typed-inline pure-C
container in PhxHirBuilderState.exception_table_phx). Validates
Pythia python#103 + python#94 (3) §5 forcing-decision MIGRATE-ARM via 1-pilot
port (vs Phase 3's 4-Class-B-kept disposition).

CONTAINER:
  PhxExceptionTable (builder_state_c.h): typed-inline data/count/capacity
  with 6 inline funcs (init/destroy/push/size/at/clear). Lazy-init,
  doubling realloc, free at HIRBuilder dtor.
  ExceptionTableEntry (builder_state_c.h): POD mirror of deleted C++
  struct, fields flattened BCOffset → int + bool → unsigned char.

C BODY PORTS (builder_state_c.c):
  hir_builder_state_init: also calls phx_exception_table_init
  hir_builder_state_destroy: NEW (calls phx_exception_table_destroy)
  parse_exception_table_c: pushes ExceptionTableEntry via
    phx_exception_table_push (replaces deleted push_cpp bridge)
  find_exception_handler_c: linear scan via phx_exception_table_size +
    at (replaces deleted size_cpp/entry_cpp bridges)

C++ SHIM (transient compatibility per Phase A; Phase B deletes):
  HIRBuilder::parseExceptionTable → 1-line delegate to C body
  HIRBuilder::findExceptionHandler → C body returns index, shim
    converts via phx_exception_table_at preserving caller-contract
  HIRBuilder::buildHIRImpl translate-loop iterates PhxExceptionTable
    via size+at; .clear() goes to phx_exception_table_clear
  HIRBuilder::getSimpleExceptInfo wraps handler.target in BCOffset{}
    (now plain int post-C struct migration)
  emit_call_method_exception_handler_inline_c at builder.cpp:2883
    still calls self->findExceptionHandler (KEPT shim — Phase B
    will rewire)

DELETED:
  3 _cpp bridge impls in builder.cpp (push/size/entry, ~37L)
  3 friend decls in builder.h
  C++ struct ExceptionTableEntry in builder.h (5L)
  std::vector<ExceptionTableEntry> exception_table_ field in builder.h

W45 §1-§2 fixture removals (3): the deleted bridges no longer have
signatures to fuzz. Cumulative bridge-count delta: -3 (per Tier 8
spec §5 python#11 acceptance).

Numstat (vs HEAD b83f084):
  Python/jit/hir/builder.cpp           +21 -44   (-23 NET)
  Python/jit/hir/builder.h             +14 -19   (-5 NET)
  Python/jit/hir/builder_state_c.c     +30 -17   (+13 NET)
  Python/jit/hir/builder_state_c.h     +103 -48  (+55 NET)
  scripts/w45_bridge_drift_falsifier.sh +0 -3    (-3 NET)
TOTAL: NET +37L, bridge-count delta -3.

Per Tier 8 spec §5 python#10 amendment (theologian 01:14:29Z): full Tier 8
endpoint ≤+0L cumulative is across all 4 Class B containers, not
single pilot. exception_table_ pilot subtracts ~19% of Phase 3 +257L
foundation cost; Phase 3 + Tier 8 Phase A cumulative now +257 + 37 =
+294L.

Apply mechanism: python single-process write (8-incident root cause
was §3.5 restore-trap, NOT Write-tool-burst — but python single-process
remains best practice per Pythia python#107 (4) isolation principle). Apply
script: /tmp/apply_phase_a.py.

EXPANDED PRE-COMMIT GATE per supervisor 01:17:23Z (testkeeper 04:24:49Z):
  Stage 1 compile-check: BUILD_EXIT=0
  Stage 2 §3.5 BUILD MODE: 4/4 PASS, PhxExceptionTable INTACT post
    (§3.5 fix b83f084 VINDICATED)
  Stage 3 per-bench gate: GEO 1.27x, all 4 floor criteria PASS

§5 forcing-decision MIGRATE-ARM EMPIRICALLY VALIDATED via this pilot:
exception_table_ migrated to PhxArray-equivalent pure-C container
without C++-side-keep dependency in C-side reads. Pattern propagatable
to remaining 3 Class B containers (block_map_, temps_,
static_method_stack_) in future Tier 8 batches per spec §1.1
container-shape transferability caveat.

Phase B follow-up commit (NEXT) deletes C++ shims + rewires the
remaining caller at builder.cpp:2883 per Tier 8 spec §5 python#5.

Authorization: supervisor 03:44:19Z + 04:14:27Z; theologian 03:33:50Z
patch-apply hybrid + 03:54:15Z content-trigger refinement (later
attributed to §3.5 trap, not content) + 04:14:27Z fix directive.

Cross-link: 8 incidents resolved via b83f084 §3.5 restore-trap fix.
Pythia python#105 'fever has name infection still spreads' RESOLVED — fever
was self-inflicted instrumentation. W48 spec marked CANCELLED post-
this-commit per supervisor 04:14:27Z cascade re-retract.