Move chrome test utilities into DDS

The Chrome test utilities (deleted in https://github.com/flutter/devtools/pull/9372, change reverted when rolling DevTools into the Dart SDK) are not being used in DevTools, but are being used in the `devtools_server` tests in DDS.

```
error - dds/test/devtools_server/instance_reuse_test.dart:73:30 - Undefined name 'Chrome'. Try correcting the name to one that is defined, or defining the name. - undefined_identifier
error - dds/test/devtools_server/instance_reuse_test.dart:117:30 - Undefined name 'Chrome'. Try correcting the name to one that is defined, or defining the name. - undefined_identifier
error - dds/test/devtools_server/server_connection_common.dart:85:28 - Undefined name 'Chrome'. Try correcting the name to one that is defined, or defining the name. - undefined_identifier
error - dds/test/devtools_server/utils/server_driver.dart:93:9 - Undefined name 'useChromeHeadless'. Try correcting the name to one that is defined, or defining the name. - undefined_identifier
error - dds/test/devtools_server/utils/server_driver.dart:93:30 - Undefined name 'headlessModeIsSupported'. Try correcting the name to one that is defined, or defining the name. - undefined_identifier

5 issues found.
```

We should consider moving these test utilities out of DevTools and into DDS.