Work towards https://github.com/dart-lang/sdk/issues/53402
I move them all out of static fields on FixProcessor to be instance
fields on a singleton class in a new file, fix_generators.dart. For
each one that ended in the word 'Map', I removed that.
I also move `_bulkFixableErrorCodes` and `canBulkFix` to
BulkFixProcessor, as it is the only caller, and holds onto the data.
I also correct some outdated doc comments.
I also make `_isFixableError` static.
Cq-Include-Trybots: luci.dart.try:flutter-analyze-try,analyzer-win-release-try,pkg-win-release-try
Change-Id: I01beccac4969f832941c75eb6d7b49b54a0b085c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/377563
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Samuel Rawlins <srawlins@google.com>
Sam Rawlins
3e58529caa