Attach flow nodes only when allowUnreachableCode !== true

Author: ahejlsberg

src/compiler/binder.ts

@@ -672,7 +672,7 @@ namespace ts {
                 bindJSDoc(node);
                 return;
             }
-            if (node.kind >= SyntaxKind.FirstStatement && node.kind <= SyntaxKind.LastStatement) {
+            if (node.kind >= SyntaxKind.FirstStatement && node.kind <= SyntaxKind.LastStatement && !options.allowUnreachableCode) {
                 node.flowNode = currentFlow;
             }
             switch (node.kind) {

src/compiler/checker.ts

@@ -30539,8 +30539,7 @@ namespace ts {
                         cancellationToken.throwIfCancellationRequested();
                 }
             }
-            if (kind >= SyntaxKind.FirstStatement && kind <= SyntaxKind.LastStatement &&
-                !compilerOptions.allowUnreachableCode && node.flowNode && !isReachableFlowNode(node.flowNode)) {
+            if (kind >= SyntaxKind.FirstStatement && kind <= SyntaxKind.LastStatement && node.flowNode && !isReachableFlowNode(node.flowNode)) {
                 errorOrSuggestion(compilerOptions.allowUnreachableCode === false, node, Diagnostics.Unreachable_code_detected);
             }