Run benchmarks with `--omit-type-checks` (#131102)

We've decided to use the `--omit-type-checks` flag for our dart2wasm benchmarks. Right now, many of the benchmark results are dominated by type checks and most of what we are actually trying to measure get drowned out in the noise.

.ci.yaml

@@ -1079,7 +1079,6 @@ targets:
 
   - name: Linux web_benchmarks_html
     recipe: devicelab/devicelab_drone
-    presubmit: false
     timeout: 60
     properties:
       dependencies: >-
@@ -1096,7 +1095,6 @@ targets:
       - .ci.yaml
 
   - name: Linux web_benchmarks_skwasm
-    bringup: true
     recipe: devicelab/devicelab_drone
     presubmit: false
     timeout: 60

dev/devicelab/lib/tasks/web_benchmarks.dart

@@ -36,6 +36,7 @@ Future<TaskResult> runWebBenchmark(WebBenchmarkOptions benchmarkOptions) async {
       if (benchmarkOptions.useWasm) ...<String>[
         '--wasm',
         '--wasm-opt=debug',
+        '--omit-type-checks',
       ],
       '--dart-define=FLUTTER_WEB_ENABLE_PROFILING=true',
       '--web-renderer=${benchmarkOptions.webRenderer}',