[csa] Make CSA::Assert depend on --debug-code.

This way it's possible to disable Assert() even in Debug
builds via --nodebug-code.

R=danno@chromium.org
BUG=v8:5268

Review-Url: https://codereview.chromium.org/2690983002
Cr-Commit-Position: refs/heads/master@{#43143}

src/code-stub-assembler.cc

@@ -47,6 +47,7 @@ void CodeStubAssembler::Assert(const NodeGenerator& codition_body,
                                const char* message, const char* file,
                                int line) {
 #if defined(DEBUG)
+  if (FLAG_debug_code) {
     Label ok(this);
     Label not_ok(this, Label::kDeferred);
     if (message != nullptr && FLAG_code_comments) {
@@ -62,7 +63,8 @@ void CodeStubAssembler::Assert(const NodeGenerator& codition_body,
       char chars[1024];
       Vector<char> buffer(chars);
       if (file != nullptr) {
-      SNPrintF(buffer, "CSA_ASSERT failed: %s [%s:%d]\n", message, file, line);
+        SNPrintF(buffer, "CSA_ASSERT failed: %s [%s:%d]\n", message, file,
+                 line);
       } else {
         SNPrintF(buffer, "CSA_ASSERT failed: %s\n", message);
       }
@@ -74,6 +76,7 @@ void CodeStubAssembler::Assert(const NodeGenerator& codition_body,
     Goto(&ok);
     Bind(&ok);
     Comment("] Assert");
+  }
 #endif
 }