Update re2

third_party/re2/patches/sparse-array-valgrind.patch

-diff --git a/third_party/re2/util/sparse_array.h b/third_party/re2/util/sparse_array.h
-index 4ee5c94..7bc3a86 100644
---- a/third_party/re2/util/sparse_array.h
-+++ b/third_party/re2/util/sparse_array.h
-@@ -273,13 +273,13 @@ void SparseArray<Value>::resize(int new_max_size) {
-     int* a = new int[new_max_size];
-     if (sparse_to_dense_) {
-       memmove(a, sparse_to_dense_, max_size_*sizeof a[0]);
--      // Don't need to zero the memory but appease Valgrind.
--      if (valgrind_) {
--        for (int i = max_size_; i < new_max_size; i++)
--          a[i] = 0xababababU;
--      }
-       delete[] sparse_to_dense_;
-     }
-+    // Don't need to zero the memory but appease Valgrind.
-+    if (valgrind_) {
-+      for (int i = max_size_; i < new_max_size; i++)
-+        a[i] = 0xababababU;
-+    }
-     sparse_to_dense_ = a;
- 
-     dense_.resize(new_max_size);