Parse JSDoc types using the normal TS parser

This means that JSDoc types can include the full range of Typescript
types now. It also means that Typescript annotations can include JSDoc
types. This is disallowed with a new error, however. But Typescript can
still give the correct types to JSDoc that shows up in .ts files by
mistake. This can easily happen, for example with types like

```ts
var x: number? = null;
var y: ?string = null;
var z: function(string,string): string = (s,t) => s + t;

// less likely to show up, but still understood.
var ka: ? = 1;
```

In the future, I will add a quick fix to convert these into the correct
types.

Fixes #16550

src/services/utilities.ts

@@ -176,7 +176,6 @@ namespace ts {
 
         switch (node.parent.kind) {
             case SyntaxKind.TypeReference:
-            case SyntaxKind.JSDocTypeReference:
                 return true;
             case SyntaxKind.ExpressionWithTypeArguments:
                 return !isExpressionWithTypeArgumentsInClassExtendsClause(<ExpressionWithTypeArguments>node.parent);