Only set types of conditional expressions in strong mode.

pkg/front_end/testcases/expressions.dart.direct.expect

 library;
 import self as self;
 import "dart:core" as core;
 
 static method foo({dynamic fisk = null}) → dynamic {
   core::print(fisk);
 }
 static method caller(dynamic f) → dynamic {
   f.call();
 }
 static method main() → dynamic {
   core::int i = 0;
-  core::print(i.==(1) ?{core::String} "bad" : "good");
+  core::print(i.==(1) ? "bad" : "good");
   core::print("${i}");
   core::print("'${i}'");
   core::print(" '${i}' ");
   core::print(" '${i}' '${i}'");
   core::print(" '${i}' '${i}'");
   core::print("foobar");
   core::print(" '${i}' '${i}' '${i}' '${i}'");
   try {
     throw "fisk";
   }
@@ skipping 46 matching lines @@
   core::print(let final dynamic #t5 = core::int in let final dynamic #t6 = #t5.toString() in #t5);
   try {
     core::print(throw new core::NoSuchMethodError::_withType(null, #toString, 32, <dynamic>[].toList(growable: false), <dynamic, dynamic>{}, null));
     throw "Shouldn't work";
   }
   on core::NoSuchMethodError catch(final dynamic e) {
     core::print("As expected: ${e}");
   }
   core::print(core::int::parse("42"));
 }