Add lexical scope and redefining variables in functions (#3015)

* Fix to allow variable shadowing inside functions

* Implement closures

* Fix KCL test code to not reference future tag definition

* Remove tag declarator from function parameters

This is an example where the scoping change revealed a subtle issue
with TagDeclarators.  You cannot bind a new tag using a function
parameter.

The issue is that evaluating a TagDeclarator like $foo binds an
identifier to its corresponding TagIdentifier, but returns the
TagDeclarator.  If you have a TagDeclarator passed in as a parameter
to a function, you can never get its corresponding TagIdentifier.

This seems like a case where TagDeclarator evaluation needs to be
revisited, especially now that we have scoped tags.

* Fix to query return, functions, and tag declarator AST nodes correctly

src/lang/std/std.test.ts

@@ -17,9 +17,9 @@ describe('testing angledLineThatIntersects', () => {
   offset: ${offset},
 }, %, "yo2")
 const intersect = segEndX('yo2', part001)`
-    const { root } = await enginelessExecutor(parse(code('-1')))
-    expect(root.intersect.value).toBe(1 + Math.sqrt(2))
-    const { root: noOffset } = await enginelessExecutor(parse(code('0')))
-    expect(noOffset.intersect.value).toBeCloseTo(1)
+    const mem = await enginelessExecutor(parse(code('-1')))
+    expect(mem.get('intersect')?.value).toBe(1 + Math.sqrt(2))
+    const noOffset = await enginelessExecutor(parse(code('0')))
+    expect(noOffset.get('intersect')?.value).toBeCloseTo(1)
   })
 })