[libFuzzer] apply changes lost during the migration to compiler-rt

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk/lib/fuzzer@311420 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/FuzzerLoop.cpp b/FuzzerLoop.cpp
index 2064783..2349459 100644
--- a/FuzzerLoop.cpp
+++ b/FuzzerLoop.cpp
@@ -388,11 +388,12 @@
   uint8_t dummy;
   ExecuteCallback(&dummy, 0);
 
-  for (const auto &U : *InitialCorpus) {
+  for (auto &U : *InitialCorpus) {
     RunOne(U.data(), U.size());
     CheckExitOnSrcPosOrItem();
     TryDetectingAMemoryLeak(U.data(), U.size(),
                             /*DuringInitialCorpusExecution*/ true);
+    U.clear();
   }
   PrintStats("INITED");
   if (Corpus.empty()) {