fix #29766, fix #29782 - fix override checker's interface checking

pkg/dev_compiler/tool/build_pkgs.dart

Index: pkg/dev_compiler/tool/build_pkgs.dart
diff --git a/pkg/dev_compiler/tool/build_pkgs.dart b/pkg/dev_compiler/tool/build_pkgs.dart
index 6cad23ee5bcf5596b9903f382fedbf54879ef690..fb60ca4917d160c03d99e2e10f6d3b7af0e92672 100755
--- a/pkg/dev_compiler/tool/build_pkgs.dart
+++ b/pkg/dev_compiler/tool/build_pkgs.dart
@@ -43,7 +43,7 @@ void main(List<String> arguments) {
   }
 
   // Under third_party/pkg.
-  compileModule('collection');
+  compileModule('collection', unsafeForceCompile: true);

[Jennifer Messerly, 2017/07/19 03:45:21]

there's a soundness bug in package:collections:

[error] Invalid override. The type of 'MapKeySet.lookup' ('(E) → E') isn't a
subtype of 'Set<E>.lookup' ('(Object) → E').
(package:collection/src/wrappers.dart, line 453, col 3)

I'll send over a fix

   compileModule('matcher');
   compileModule('path');
   if (isTravis) {