test/devtools_test.dart: Injected client can not launch devtools for the same app in multiple tabs

Last portion of log output from the failing test:

```
...
[INFO] DwdsInjector: Injected debugging metadata for entrypoint at http://localhost:36443/hello_world/main.dart.bootstrap.js

[FINEST] TestServer: 0:00:00.010396 GET [304] /hello_world/main.dart.bootstrap.js

[FINEST] TestServer: 0:00:00.003443 GET [304] /hello_world/main.ddc.js

[FINEST] TestServer: 0:00:00.002744 GET [304] /packages/build_web_compilers/src/dev_compiler/dart_sdk.js

[FINEST] TestServer: 0:00:00.002198 GET [304] /packages/intl/src/intl/bidi.ddc.js

[FINEST] TestServer: 0:00:00.002243 GET [304] /packages/path/path.ddc.js

[FINEST] TestServer: 0:00:00.004362 GET [304] /packages/intl/number_symbols_data.ddc.js

[FINEST] TestServer: 0:00:00.004541 GET [304] /packages/intl/src/date_format_internal.ddc.js

[FINEST] TestServer: 0:00:00.003802 GET [304] /packages/clock/clock.ddc.js

[FINEST] TestServer: 0:00:00.002615 GET [304] /packages/intl/date_symbols.ddc.js

[FINEST] TestServer: 0:00:00.001989 GET [304] /packages/intl/number_symbols.ddc.js

[FINEST] TestServer: 0:00:00.010031 GET [200] /dwds/src/injected/client.js

[FINEST] TestServer: 0:00:00.003327 GET [200] /hello_world/$requireDigestsPath?entrypoint=hello_world/main.dart.bootstrap.js

[FINEST] TestServer: 0:00:00.000510 POST [200] /hello_world/$dwdsSseHandler?sseClientId=InjectedClient-13e9d860-b9d8-441f-83a5-2a828c3f8692&messageId=0

[FINEST] TestServer: 0:00:00.000583 POST [200] /hello_world/$dwdsSseHandler?sseClientId=InjectedClient-13e9d860-b9d8-441f-83a5-2a828c3f8692&messageId=1

[INFO] DevHandler: Stopped debug service on ws://127.0.0.1:44456

[FINE] ChromeProxyService: Destroying isolate
Bad state: Page never initialized
test/devtools_test.dart 28:3 _waitForPageReady
===== asynchronous gap ===========================
test/devtools_test.dart 76:9 main..
Bad state: Page never initialized
test/devtools_test.dart 28:3 _waitForPageReady
===== asynchronous gap ===========================
test/devtools_test.dart 76:9 main..
Bad state: Page never initialized
test/devtools_test.dart 28:3 _waitForPageReady
===== asynchronous gap ===========================
test/devtools_test.dart 76:9 main..
Bad state: Page never initialized
test/devtools_test.dart 28:3 _waitForPageReady
===== asynchronous gap ===========================
test/devtools_test.dart 76:9 main..
```

Marking this test as skipped until the failure can be properly investigated.