LSP fix all in workspace test time out on 5 seconds

[FMorschel]

While working on https://dart-review.googlesource.com/c/sdk/+/401865 I added a test to pkg\analysis_server\test\lsp\commands\fix_all_in_workspace_test.dart as suggested by @DanTup at https://dart-review.googlesource.com/c/sdk/+/401840 for better debugging than the dart fix tests since they should work the same way.

While testing I added @soloTest to the newly added test AbstractLspAnalysisServerTest.test_partFile_issue59572. And gave a try to add argument: ['./lib/part.dart'] to the Command constructor on it. That can reliably reproduce the failure for the 5-second timeout on my machine. The stack trace:

TimeoutException after 0:00:05.000000: Future not completed

  dart:async/future_impl.dart 1025:22                               Future.timeout.<fn>
future_impl.dart:1025
  ===== asynchronous gap ===========================
  test\lsp\server_abstract.dart 1139:29                             LspAnalysisServerTestMixin.expectRequest
server_abstract.dart:1139
  ===== asynchronous gap ===========================
  test\lsp\server_abstract.dart 1181:27                             LspAnalysisServerTestMixin.handleExpectedRequest
server_abstract.dart:1181
  ===== asynchronous gap ===========================
  test\lsp\server_abstract.dart 155:27                              AbstractLspAnalysisServerTest.executeForEdits
server_abstract.dart:155
  ===== asynchronous gap ===========================
  test\lsp\server_abstract.dart 369:20                              AbstractLspAnalysisServerTest.verifyCommandEdits
server_abstract.dart:369
  ===== asynchronous gap ===========================
  test\lsp\commands\fix_all_in_workspace_test.dart 169:5            AbstractFixAllInWorkspaceTest.test_partFile_issue59572
fix_all_in_workspace_test.dart:169
  ===== asynchronous gap ===========================
  package:test_reflective_loader/test_reflective_loader.dart 261:5  _runTest
test_reflective_loader.dart:261
  ===== asynchronous gap ===========================
  package:test_api/src/backend/declarer.dart 229:9                  Declarer.test.<fn>.<fn>
declarer.dart:229
  ===== asynchronous gap ===========================
  package:test_api/src/backend/declarer.dart 227:7                  Declarer.test.<fn>
declarer.dart:227
  ===== asynchronous gap ===========================
  package:test_api/src/backend/invoker.dart 258:9                   Invoker._waitForOutstandingCallbacks.<fn>
invoker.dart:258

The place where it is failing pkg\analysis_server\test\lsp\server_abstract.dart, line 1139, inside LspAnalysisServerTestMixin.expectRequest. The expectRequest contains a timeout that defaults to that value but the method that calls it (LspAnalysisServerTestMixin.handleExpectedRequest) also has a timeout parameter that is not passing through (in this case not even in use).

After a talk with @DanTup on Discord about this, we think it may be safe to increase that value. We'll also take a look at the timings here and why adding these (@soloTest and parameters) slows down the execution. Creating this issue to track this work.

---

As a note, if we increase it a lot (tested with 5 min) the tests themselves fail at 30 seconds. The take from @DanTup was that this was intended to give some indication as to where would it be taking a long time to answer.