fix(llvm): make LLVM EXE smokes use workspace target and reliable build_llvm

tools/smokes/v2/lib/llvm_exe_runner.sh

@@ -12,9 +12,8 @@
 set -uo pipefail
 
 llvm_exe_cargo_target_dir() {
-  # Release builds can fail with EXDEV when rustc uses /tmp for temp files and target/ is elsewhere.
-  # Force a dedicated target dir under /tmp so rustc temp files and outputs stay on the same filesystem.
-  local target_dir="${LLVM_EXE_CARGO_TARGET_DIR:-/tmp/nyash_cargo_target}"
+  # Use the workspace target dir by default so `NYASH_BIN` and plugin artifacts match local dev expectations.
+  local target_dir="${LLVM_EXE_CARGO_TARGET_DIR:-$NYASH_ROOT/target}"
   mkdir -p "$target_dir"
   echo "$target_dir"
 }
@@ -25,32 +24,11 @@ llvm_exe_preflight_or_skip() {
     return 1
   fi
 
-  if ! "$NYASH_BIN" --help 2>&1 | grep -q "llvm"; then
-    test_skip "hakorune --backend llvm not available"
-    return 1
-  fi
-
   if ! python3 -c "import llvmlite" 2>/dev/null; then
     test_skip "Python llvmlite not found"
     return 1
   fi
 
-  # Verify the binary can actually emit an object (not "mock LLVM").
-  # This avoids hard failures when hakorune was built without `--features llvm`.
-  local cargo_target_dir
-  cargo_target_dir="$(llvm_exe_cargo_target_dir)"
-  local preflight_obj="$cargo_target_dir/_llvm_exe_preflight.o"
-  rm -f "$preflight_obj"
-  if ! env NYASH_DISABLE_PLUGINS=1 NYASH_LLVM_USE_HARNESS=1 NYASH_LLVM_OBJ_OUT="$preflight_obj" \
-    "$NYASH_BIN" --backend llvm "$NYASH_ROOT/apps/tests/phase87_llvm_exe_min.hako" >/dev/null 2>&1; then
-    test_skip "LLVM object emit preflight failed (hakorune may lack --features llvm)"
-    return 1
-  fi
-  if [ ! -f "$preflight_obj" ]; then
-    test_skip "LLVM object emit unavailable (hakorune may be built without --features llvm)"
-    return 1
-  fi
-
   return 0
 }