Backed out changeset 4d9aebc3fabb (bug 1516644) for causing build bustages.

js/src/jit/MIRGraph.cpp

@@ -489,7 +489,7 @@ MBasicBlock::MBasicBlock(MIRGraph& graph, const CompileInfo& info,
       trackedSite_(site),
       hitCount_(0),
       hitState_(HitState::NotDefined)
-#if defined(JS_ION_PERF) || defined(DEBUG)
+#if defined(JS_ION_PERF)
       ,
       lineno_(0u),
       columnIndex_(0u)