[benchmarks] Use #if to conditionalise instead of builder/bot name

This is for consistency with similar code in fuchsia.git, being
changed here:
https://fuchsia-review.googlesource.com/c/fuchsia/+/313906

Bug: 35472
Test: topaz-perf trybot
Change-Id: I5ad273d4cde4642a0a55e7c2e453c9281382f329
diff --git a/tests/benchmarks/benchmarks.cc b/tests/benchmarks/benchmarks.cc
index 5568c9a..2b74134 100644
--- a/tests/benchmarks/benchmarks.cc
+++ b/tests/benchmarks/benchmarks.cc
@@ -28,20 +28,18 @@
     FXL_LOG(INFO) << "Vulkan not supported; graphics tests skipped.";
   }
 
-  std::string benchmarks_bot_name = benchmarks_runner.benchmarks_bot_name();
-
   // TODO(PT-118): Input latency tests are only currently supported on NUC.
-  if (benchmarks_bot_name == "topaz-x64-perf-dawson_canyon") {
-    constexpr const char* kLabel = "fuchsia.input_latency.button_flutter";
-    std::string out_file = benchmarks_runner.MakeTempFile();
-    benchmarks_runner.AddCustomBenchmark(
-        kLabel,
-        {"/bin/run",
-         "fuchsia-pkg://fuchsia.com/topaz_input_latency_benchmarks#meta/"
-         "run_button_flutter_benchmark.cmx",
-         "--out_file", out_file, "--benchmark_label", kLabel},
-        out_file);
-  }
+#if !defined(__aarch64__)
+  constexpr const char* kLabel = "fuchsia.input_latency.button_flutter";
+  std::string out_file = benchmarks_runner.MakeTempFile();
+  benchmarks_runner.AddCustomBenchmark(
+      kLabel,
+      {"/bin/run",
+       "fuchsia-pkg://fuchsia.com/topaz_input_latency_benchmarks#meta/"
+       "run_button_flutter_benchmark.cmx",
+       "--out_file", out_file, "--benchmark_label", kLabel},
+      out_file);
+#endif
 
   benchmarks_runner.Finish();
 }