Fix issue 1076 by resetting labels of switch-clauses before use....

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
===================================================================
--- src/x64/full-codegen-x64.cc	(revision 6492)
+++ src/x64/full-codegen-x64.cc	(working copy)
@@ -710,6 +710,8 @@
   // Compile all the tests with branches to their bodies.
   for (int i = 0; i < clauses->length(); i++) {
     CaseClause* clause = clauses->at(i);
+    clause->body_target()->entry_label()->Unuse();
+
     // The default is not a test, but remember it as final fall through.
     if (clause->is_default()) {
       default_clause = clause;