[dartdevc] enable testing on ff/safari/edge

Change-Id: Ice9cc8f4955561a7d36b7ab2bc7a0622cc4966b0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/105482
Auto-Submit: Vijay Menon <vsm@google.com>
Commit-Queue: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Bob Nystrom <rnystrom@google.com>

pkg/smith/lib/configuration.dart

@@ -656,6 +656,9 @@ class Compiler extends NamedEnum {
         return const [
           Runtime.none,
           Runtime.chrome,
+          Runtime.edge,
+          Runtime.firefox,
+          Runtime.safari,
         ];
 
       case Compiler.dart2analyzer: