Fix -Wsign-compare warnings in parser, scanner, regexp, runtime.

src/runtime/runtime-regexp.cc

Index: src/runtime/runtime-regexp.cc
diff --git a/src/runtime/runtime-regexp.cc b/src/runtime/runtime-regexp.cc
index 0f90087d84e9921d7f55d34c33915ecc06eb9369..d572eedd31c6971b9f6fc45592a107dfa2a2e468 100644
--- a/src/runtime/runtime-regexp.cc
+++ b/src/runtime/runtime-regexp.cc
@@ -391,7 +391,7 @@ List<int>* GetRewoundRegexpIndicesList(Isolate* isolate) {
 void TruncateRegexpIndicesList(Isolate* isolate) {
   // Same size as smallest zone segment, preserving behavior from the
   // runtime zone.
-  static const size_t kMaxRegexpIndicesListCapacity = 8 * KB;
+  static const int kMaxRegexpIndicesListCapacity = 8 * KB;
   if (isolate->regexp_indices()->capacity() > kMaxRegexpIndicesListCapacity) {
     isolate->regexp_indices()->Clear();  //  Throw away backing storage
   }