[Test] Remove some dead code.

Change-Id: I619a06fecce3d006ab573163a33e01f70d6af9d5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/103180
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Siva Annamalai <asiva@google.com>
diff --git a/tools/testing/dart/compiler_configuration.dart b/tools/testing/dart/compiler_configuration.dart
index ca2437b..7c55c86 100644
--- a/tools/testing/dart/compiler_configuration.dart
+++ b/tools/testing/dart/compiler_configuration.dart
@@ -188,11 +188,6 @@
       List<String> originalArguments,
       CommandArtifact artifact) {
     var args = <String>[];
-    if (_isDebug) {
-      // Temporarily disable background compilation to avoid flaky crashes
-      // (see http://dartbug.com/30016 for details).
-      args.add('--no-background-compilation');
-    }
     if (_useEnableAsserts) {
       args.add('--enable_asserts');
     }