Add support for enabling DCHECKs in release mode

src/full-codegen.cc

Index: src/full-codegen.cc
diff --git a/src/full-codegen.cc b/src/full-codegen.cc
index cb8f4aafcd9cd7274f032f14505f5dd028725252..77f173d91c375a443604f1e1415976f324523217 100644
--- a/src/full-codegen.cc
+++ b/src/full-codegen.cc
@@ -1759,7 +1759,7 @@ void BackEdgeTable::RemoveStackCheck(Handle<Code> code, uint32_t pc_offset) {
 }
 
 
-#ifdef DEBUG
+#if DCHECK_IS_ON
 bool BackEdgeTable::Verify(Isolate* isolate, Code* unoptimized) {
   DisallowHeapAllocation no_gc;
   int loop_nesting_level = unoptimized->allow_osr_at_loop_nesting_level();
@@ -1776,7 +1776,7 @@ bool BackEdgeTable::Verify(Isolate* isolate, Code* unoptimized) {
   }
   return true;
 }
-#endif  // DEBUG
+#endif  // DCHECK_IS_ON
 
 
 FullCodeGenerator::EnterBlockScopeIfNeeded::EnterBlockScopeIfNeeded(