Add strong mode type checking pass.

testcases/strong-mode/DeltaBlue.baseline.txt

+// dynamic is not a subtype of dart.core::int (DeltaBlue.dart:126:17)
+// dynamic is not a subtype of dart.core::int (DeltaBlue.dart:133:15)
+// dynamic is not a subtype of dart.core::int (DeltaBlue.dart:138:36)
+// dynamic is not a subtype of dart.core::int (DeltaBlue.dart:139:15)

[asgerf, 2016/11/01 14:29:08]

These are due to implicit casts not being inserted.

 library;
 import self as self;
 import "dart:core" as core;
 
 class DeltaBlue extends core::Object {
   constructor •() → void
     : super core::Object::•()
     ;
   method run() → void {
     self::chainTest(100);
@@ skipping 430 matching lines @@
 }
 static method change(self::Variable v, core::int newValue) → void {
   self::EditConstraint edit = new self::EditConstraint::•(v, self::PREFERRED);
   self::Plan plan = self::planner.{self::Planner::extractPlanFromConstraints}(<self::EditConstraint>[edit]);
   for (core::int i = 0; i.{core::num::<}(10); i = i.{core::num::+}(1)) {
     v.{self::Variable::value} = newValue;
     plan.{self::Plan::execute}();
   }
   edit.{self::Constraint::destroyConstraint}();
 }