Move all flags to CompilerOptions (first step to stop passing the compiler to

pkg/compiler/lib/src/compile_time_constants.dart

Index: pkg/compiler/lib/src/compile_time_constants.dart
diff --git a/pkg/compiler/lib/src/compile_time_constants.dart b/pkg/compiler/lib/src/compile_time_constants.dart
index d633e6b1394eab126a3a3b88fffc02f70b9ce6bc..1eabdf3ef2c6fc7fe9a88adaa8749023c90812ee 100644
--- a/pkg/compiler/lib/src/compile_time_constants.dart
+++ b/pkg/compiler/lib/src/compile_time_constants.dart
@@ -243,7 +243,7 @@ abstract class ConstantCompilerBase implements ConstantCompiler {
     } else {
       expression = compileNodeWithDefinitions(initializer, definitions,
           isConst: isConst);
-      if (compiler.enableTypeAssertions &&
+      if (compiler.options.enableTypeAssertions &&
           checkType &&
           expression != null &&
           element.isField) {
@@ -1079,7 +1079,7 @@ class ConstructorEvaluator extends CompileTimeConstantEvaluator {
   }
 
   void potentiallyCheckType(TypedElement element, AstConstant constant) {
-    if (compiler.enableTypeAssertions) {
+    if (compiler.options.enableTypeAssertions) {
       DartType elementType = element.type.substByContext(constructedType);
       DartType constantType = constant.value.getType(coreTypes);
       if (!constantSystem.isSubtype(