Remove var or final from parameters.

Removed from `benchmarks/`, `runtime/`, `sdk/`, `tools/` and `utils/`.
(Leaving `tests/`, `pkg/` and `third_party/`.)

CoreLibraryReviewExempt: No real change.
Tested: No test changes for no real code changes.
Change-Id: Ieb42441457ca3d0ea4443dd153ee902ea33b28de
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/480241
Commit-Queue: Lasse Nielsen <lrn@google.com>
Reviewed-by: Ben Konyi <bkonyi@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>

utils/compiler/create_snapshot_entry.dart

@@ -9,7 +9,7 @@
 import 'dart:io';
 import 'dart:async';
 
-Future<String> getVersion(var rootPath, bool noGitHash) {
+Future<String> getVersion(rootPath, bool noGitHash) {
   var printVersionScript = rootPath.resolve("tools/make_version.py");
   var args = <String>[
     printVersionScript.toFilePath(),
@@ -25,7 +25,7 @@ Future<String> getVersion(var rootPath, bool noGitHash) {
   });
 }
 
-Future<String> getDart2jsSnapshotGenerationFile(var rootPath, bool noGitHash) {
+Future<String> getDart2jsSnapshotGenerationFile(rootPath, bool noGitHash) {
   return getVersion(rootPath, noGitHash).then((version) {
     var snapshotGenerationText =
         """