Fix 8355: Fix emit metadata different between transpile and tsc --isolatedModule (#9232)

* Instead of returning undefined for unknownSymbol return itself

* Add Transpile unittest

* Wip - Add project tests

* Add project tests and baselines

* Update existed tests

* Add tests for emitting metadata with module targetting system

src/compiler/checker.ts

@@ -1265,9 +1265,13 @@ namespace ts {
                 const right = name.kind === SyntaxKind.QualifiedName ? (<QualifiedName>name).right : (<PropertyAccessExpression>name).name;
 
                 const namespace = resolveEntityName(left, SymbolFlags.Namespace, ignoreErrors);
-                if (!namespace || namespace === unknownSymbol || nodeIsMissing(right)) {
+                if (!namespace || nodeIsMissing(right)) {
                     return undefined;
                 }
+                else if (namespace === unknownSymbol) {
+                    return namespace;
+                }
+
                 symbol = getSymbol(getExportsOfSymbol(namespace), right.text, meaning);
                 if (!symbol) {
                     if (!ignoreErrors) {