[BUILD] Fix benchmark genrule capturing stderr into JSON output (open-telemetry#3925)

Author: ThomsonTan

CHANGELOG.md

@@ -15,6 +15,9 @@ Increment the:
 
 ## [Unreleased]
 
+* [BUILD] Fix benchmark genrule capturing stderr into JSON output
+  [#3925](https://github.com/open-telemetry/opentelemetry-cpp/pull/3925)
+
 * [TEST] Add multi-threaded metrics benchmarks for shared vs per-thread counter
   [#3865](https://github.com/open-telemetry/opentelemetry-cpp/pull/3865)
 

bazel/otel_cc_benchmark.bzl

@@ -40,7 +40,7 @@ def otel_cc_benchmark(name, srcs, deps, tags = [""]):
         tools = [":" + name],
         tags = tags + ["benchmark_result", "manual"],
         testonly = True,
-        cmd = "$(location :" + name + (") --benchmark_format=json --benchmark_color=false --benchmark_min_time=.1s &> $@"),
+        cmd = "$(location :" + name + (") --benchmark_format=json --benchmark_color=false --benchmark_min_time=.1s > $@ 2>/dev/null"),
     )
 
     # This is run as part of "bazel test ..." to smoke-test benchmarks. It's