Use failedAt in more places

pkg/compiler/lib/src/ssa/locals_handler.dart

Index: pkg/compiler/lib/src/ssa/locals_handler.dart
diff --git a/pkg/compiler/lib/src/ssa/locals_handler.dart b/pkg/compiler/lib/src/ssa/locals_handler.dart
index 52e769c7b67b9926bad13a9a31574aaefd81aea5..c2e770d90efb58c3d18f717f5b421a91104359d6 100644
--- a/pkg/compiler/lib/src/ssa/locals_handler.dart
+++ b/pkg/compiler/lib/src/ssa/locals_handler.dart
@@ -323,12 +323,12 @@ class LocalsHandler {
     if (isAccessedDirectly(local)) {
       if (directLocals[local] == null) {
         if (local is TypeVariableLocal) {
-          throw new SpannableAssertionFailure(
+          failedAt(
               CURRENT_ELEMENT_SPANNABLE,
               "Runtime type information not available for $local "
               "in $executableContext.");
         } else {
-          throw new SpannableAssertionFailure(
+          failedAt(
               local,
               "Cannot find value $local in ${directLocals.keys} for "
               "$executableContext.");