Revert "Reland "[VM/SDK]""

This reverts commit b59583edea.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> Reland "[VM/SDK]"
> 
> This is a reland of b4146411d0
> 
> Original change's description:
> > [VM/SDK]
> > 
> > - Switch the kernel isolate to run in Dart2 mode
> > - Refactor build rules so bootstrapping of the front end happens
> >   with a prebuilt dart sdk
> > - Refactor application snapshot build rules so the kernel application
> >   snapshot rule does not get into a cyclic dependency during the
> >   bootstrap stage
> > 
> > Change-Id: Id16b2859e0b299b2d689971d03a247cb94d0aa26
> > Reviewed-on: https://dart-review.googlesource.com/61660
> > Commit-Queue: Siva Annamalai <asiva@google.com>
> > Reviewed-by: Zach Anderson <zra@google.com>
> 
> Change-Id: I2a3fa8ed4f331cf3de89ddff5cf8e478809dae39
> Reviewed-on: https://dart-review.googlesource.com/65841
> Reviewed-by: Siva Annamalai <asiva@google.com>

TBR=zra@google.com,asiva@google.com

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

Change-Id: I6077236481bec9089ead881c902036b0817114fc
Reviewed-on: https://dart-review.googlesource.com/66240
Reviewed-by: Siva Annamalai <asiva@google.com>
Reviewed-by: Zach Anderson <zra@google.com>
Commit-Queue: Siva Annamalai <asiva@google.com>

utils/dartanalyzer/BUILD.gn

@@ -21,6 +21,7 @@ analyzer_files = exec_script("../../tools/list_dart_files.py",
                              "list lines")
 
 application_snapshot("generate_dartanalyzer_snapshot") {
+  dart_version = 2
   main_dart = "../../pkg/analyzer_cli/bin/analyzer.dart"
   training_args = [
     "--dart-sdk=" + rebase_path("../../sdk"),