Argh. I overlooked the constructor and destructor.

Change-Id: I3ceb50c46beda7152074329cdb0899b2c973f3f4
Reviewed-on: https://code-review.googlesource.com/c/re2/+/56482
Reviewed-by: Paul Wankadia <junyer@google.com>
diff --git a/re2/nfa.cc b/re2/nfa.cc
index 6564757..3959a78 100644
--- a/re2/nfa.cc
+++ b/re2/nfa.cc
@@ -144,13 +144,16 @@
                prog_->inst_count(kInstNop) + 1;  // + 1 for start inst
   stack_ = PODArray<AddState>(nstack);
   free_threads_ = NULL;
+  match_ = NULL;
   matched_ = false;
 }
 
 NFA::~NFA() {
+  delete[] match_;
   Thread* next;
   for (Thread* t = free_threads_; t; t = next) {
     next = t->next;
+    delete[] t->capture;
     delete t;
   }
 }