Use failedAt in more places

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

Index: pkg/compiler/lib/src/ssa/variable_allocator.dart
diff --git a/pkg/compiler/lib/src/ssa/variable_allocator.dart b/pkg/compiler/lib/src/ssa/variable_allocator.dart
index ad6140aa2e1fb3531f13df220c1aa3973ead8907..d631bc9907c2f07767253859c011e833b7aa3475 100644
--- a/pkg/compiler/lib/src/ssa/variable_allocator.dart
+++ b/pkg/compiler/lib/src/ssa/variable_allocator.dart
@@ -214,8 +214,7 @@ class SsaLiveIntervalBuilder extends HBaseVisitor {
   void visitGraph(HGraph graph) {
     visitPostDominatorTree(graph);
     if (!liveInstructions[graph.entry].isEmpty) {
-      throw new SpannableAssertionFailure(
-          CURRENT_ELEMENT_SPANNABLE, 'LiveIntervalBuilder.');
+      failedAt(CURRENT_ELEMENT_SPANNABLE, 'LiveIntervalBuilder.');
     }
   }