Exclude benchmark tests by default, add --benchmarks flag (facebook#55725)

Summary:

changelog: [internal]

By default, `yarn fantom` now excludes benchmark tests (`*-benchmark-itest.js` files) to speed up regular test runs.

Benchmark tests are typically slower and used for performance analysis rather than correctness testing. Excluding them by default improves the developer experience for everyday test runs.

To run benchmark tests, use the new `--benchmarks` flag:
```
yarn fantom --benchmarks
```

Reviewed By: andrewdacenko

Differential Revision: D92150163

Author: sammy-SC

scripts/fantom.sh

@@ -16,4 +16,20 @@ fi
 
 export NODE_OPTIONS='--max-old-space-size=8192'
 
-yarn jest --config private/react-native-fantom/config/jest.config.js "$@"
+# Parse arguments to check for --benchmarks flag
+INCLUDE_BENCHMARKS=false
+ARGS=()
+for arg in "$@"; do
+  if [[ "$arg" == "--benchmarks" ]]; then
+    INCLUDE_BENCHMARKS=true
+  else
+    ARGS+=("$arg")
+  fi
+done
+
+# By default, exclude benchmark tests unless --benchmarks is passed
+if [[ "$INCLUDE_BENCHMARKS" == false ]]; then
+  ARGS+=("--testPathIgnorePatterns" "benchmark-itest")
+fi
+
+yarn jest --config private/react-native-fantom/config/jest.config.js "${ARGS[@]}"