Update bench_runner/scripts/run_benchmarks.py

Co-authored-by: Copilot <[email protected]>

Author: mdboom

bench_runner/scripts/run_benchmarks.py

@@ -191,7 +191,7 @@ def get_perf_lines(files: Iterable[PathLike]) -> Iterable[str]:
         assert p.stdout is not None  # for pyright
         yield from iter(p.stdout.readline, "")
         p.kill()
-
+        p.wait()
 
 def perf_to_csv(lines: Iterable[str], output: PathLike):
     rows = []