Remove unused bazel test target (#6140)

* Remove benc htarget

slasher/rpc/BUILD.bazel

@@ -37,30 +37,6 @@ go_library(
     ],
 )
 
-# gazelle:exclude detect_update_min_max_span_bench_test.go
-go_test(
-    name = "go_benchmark_test",
-    size = "medium",
-    srcs = ["slashing_bench_test.go"],
-    args = [
-        "-test.bench=.",
-        "-test.benchmem",
-        "-test.v",
-    ],
-    embed = [":go_default_library"],
-    local = True,
-    tags = [
-        "benchmark",
-        "manual",
-        "no-cache",
-    ],
-    deps = [
-        "//slasher/db:go_default_library",
-        "//slasher/flags:go_default_library",
-        "@com_github_urfave_cli//:go_default_library",
-    ],
-)
-
 go_test(
     name = "go_default_test",
     srcs = [