Revert "Cache expression compilers in incremental DDC mode"

This reverts commit e6f779bcdd9ecd09e394c163c93c496a91b9ed91.

Reason for revert: Broke expression compilation in google3

Original change's description:
> Cache expression compilers in incremental DDC mode
>
> - cache expression compilers in expression compiler worker
>   to improve performance of exression compilation.
> - pass module format in expression compiler worker
>   (the ddc format tests were not running!)
> - fix an issue where the same library was imported twice
>   in module_builder.dart
> - add verbose mode timeline logging to ProgramCompiler.
> - update tests.
>
> Closes: https://github.com/dart-lang/sdk/issues/49944
> Change-Id: Ie7408dcd42e757b1eb5e7f5ccbc1b078b6417011
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/268361
> Reviewed-by: Johnni Winther <johnniwinther@google.com>
> Reviewed-by: Mark Zhou <markzipan@google.com>
> Commit-Queue: Anna Gringauze <annagrin@google.com>
> Reviewed-by: Nicholas Shahan <nshahan@google.com>

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I6c7209ffb03416dbb8d34c1a6f520f21766d9190
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/270840
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Anna Gringauze <annagrin@google.com>
Reviewed-by: Anna Gringauze <annagrin@google.com>