Restructure resident web runner usage to avoid SDK users that don't support dwds

[jonahwilliams]

Description

dwds doesn't exist in google3, which means I'll need to restructure the code so we can exclude it from the internal tool. To avoid a revert/reland/revert cycle I can remove the imports for now

[fluttergithubbot]

It looks like this pull request may not have tests. Please make sure to add tests before merging. While there are exceptions to this rule, if this patch modifies code it is probably not an exception.

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

[codecov]

Codecov Report

Merging #37815 into master will increase coverage by 0.2%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master   #37815     +/-   ##
=========================================
+ Coverage   55.52%   55.72%   +0.2%     
=========================================
  Files         193      194      +1     
  Lines       18168    18172      +4     
=========================================
+ Hits        10087    10127     +40     
+ Misses       8081     8045     -36

Flag	Coverage Δ
#flutter_tool	55.72% <0%> (+0.2%)	⬆️

Impacted Files	Coverage Δ
...ges/flutter_tools/lib/src/build_runner/web_fs.dart	24.24% <ø> (ø)
packages/flutter_tools/lib/executable.dart	92.85% <0%> (-2.27%)	⬇️
packages/flutter_tools/lib/src/commands/run.dart	60.09% <0%> (ø)	⬆️
...ackages/flutter_tools/lib/src/commands/daemon.dart	34.18% <0%> (+12.37%)	⬆️
...ools/lib/src/build_runner/resident_web_runner.dart	68.5% <0%> (ø)
packages/flutter_tools/lib/src/web/web_runner.dart	0% <0%> (ø)
packages/flutter_tools/lib/src/base/logger.dart	57.63% <0%> (-24.81%)	⬇️
packages/flutter_tools/lib/src/version.dart	90.73% <0%> (-1.96%)	⬇️
packages/flutter_tools/lib/src/cache.dart	41.99% <0%> (-0.73%)	⬇️
packages/flutter_tools/lib/src/vmservice.dart	37.15% <0%> (-0.16%)	⬇️
... and 10 more

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[jonahwilliams]

cc @yjbanov PTAL

[jonahwilliams]

cc @darrenaustin

[yjbanov]

So the messages are not confusing to non-google3 users, let's refer to it as "SDK users that don't support dwds" in the PR description and comments.