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.

1 files changed, 4 insertions, 7 deletions

diff --git a/ext/node/polyfills/_fs/_fs_mkdtemp.ts b/ext/node/polyfills/_fs/_fs_mkdtemp.ts
index de227b216..bf80d3b74 100644
--- a/ext/node/polyfills/_fs/_fs_mkdtemp.ts
+++ b/ext/node/polyfills/_fs/_fs_mkdtemp.ts
@@ -5,16 +5,13 @@ import {
   TextDecoder,
   TextEncoder,
 } from "internal:deno_web/08_text_encoding.js";
-import { existsSync } from "internal:deno_node/polyfills/_fs/_fs_exists.ts";
-import {
-  mkdir,
-  mkdirSync,
-} from "internal:deno_node/polyfills/_fs/_fs_mkdir.ts";
+import { existsSync } from "internal:deno_node/_fs/_fs_exists.ts";
+import { mkdir, mkdirSync } from "internal:deno_node/_fs/_fs_mkdir.ts";
 import {
   ERR_INVALID_ARG_TYPE,
   ERR_INVALID_OPT_VALUE_ENCODING,
-} from "internal:deno_node/polyfills/internal/errors.ts";
-import { promisify } from "internal:deno_node/polyfills/internal/util.mjs";
+} from "internal:deno_node/internal/errors.ts";
+import { promisify } from "internal:deno_node/internal/util.mjs";
 
 export type mkdtempCallback = (
   err: Error | null,