refactor(core): include_js_files! 'dir' option doesn't change specifiers (#18019)

This commit changes "include_js_files!" macro from "deno_core"
in a way that "dir" option doesn't cause specifiers to be rewritten 
to include it.

Example:
```
include_js_files! {
  dir "js",
  "hello.js",
}
```

The above definition required embedders to use:
`import ... from "internal:<ext_name>/js/hello.js"`. 
But with this change, the "js" directory in which the files are stored
is an implementation detail, which for embedders results in: 
`import ... from "internal:<ext_name>/hello.js"`.

The directory the files are stored in, is an implementation detail and 
in some cases might result in a significant size difference for the 
snapshot. As an example, in "deno_node" extension, we store the 
source code in "polyfills" directory; which resulted in each specifier 
to look like "internal:deno_node/polyfills/<module_name>", but with 
this change it's "internal:deno_node/<module_name>". 

Given that "deno_node" has over 100 files, many of them having 
several import specifiers to the same extension, this change removes
10 characters from each import specifier.

3 files changed, 4 insertions, 4 deletions

diff --git a/ext/node/polyfills/_util/_util_callbackify.ts b/ext/node/polyfills/_util/_util_callbackify.ts
index fe83a227d..84ec0274d 100644
--- a/ext/node/polyfills/_util/_util_callbackify.ts
+++ b/ext/node/polyfills/_util/_util_callbackify.ts
@@ -23,7 +23,7 @@
 
 // These are simplified versions of the "real" errors in Node.
 
-import { nextTick } from "internal:deno_node/polyfills/_next_tick.ts";
+import { nextTick } from "internal:deno_node/_next_tick.ts";
 
 class NodeFalsyValueRejectionError extends Error {
   public reason: unknown;
diff --git a/ext/node/polyfills/_util/std_asserts.ts b/ext/node/polyfills/_util/std_asserts.ts
index 8c4c80078..bd0a4fc6f 100644
--- a/ext/node/polyfills/_util/std_asserts.ts
+++ b/ext/node/polyfills/_util/std_asserts.ts
@@ -1,12 +1,12 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 // vendored from std/testing/asserts.ts
 
-import { red } from "internal:deno_node/polyfills/_util/std_fmt_colors.ts";
+import { red } from "internal:deno_node/_util/std_fmt_colors.ts";
 import {
   buildMessage,
   diff,
   diffstr,
-} from "internal:deno_node/polyfills/_util/std_testing_diff.ts";
+} from "internal:deno_node/_util/std_testing_diff.ts";
 
 /** Converts the input into a string. Objects, Sets and Maps are sorted so as to
  * make tests less flaky */
diff --git a/ext/node/polyfills/_util/std_testing_diff.ts b/ext/node/polyfills/_util/std_testing_diff.ts
index 766b5efdc..a536f70ba 100644
--- a/ext/node/polyfills/_util/std_testing_diff.ts
+++ b/ext/node/polyfills/_util/std_testing_diff.ts
@@ -9,7 +9,7 @@ import {
   green,
   red,
   white,
-} from "internal:deno_node/polyfills/_util/std_fmt_colors.ts";
+} from "internal:deno_node/_util/std_fmt_colors.ts";
 
 interface FarthestPoint {
   y: number;