refactor: move denort to separate crate (#27688)

This slightly degrades the performance of CJS export analysis on
subsequent runs because I changed it to no longer cache in the DENO_DIR
with this PR (denort now properly has no idea about the DENO_DIR). We'll
have to change it to embed this data in the binary and that will also
allow us to get rid of swc in denort (will do that in a follow-up PR).

cli/lib/util/text_encoding.rs

@@ -0,0 +1,45 @@
+// Copyright 2018-2025 the Deno authors. MIT license.
+
+use std::borrow::Cow;
+use std::sync::Arc;
+
+#[inline(always)]
+pub fn from_utf8_lossy_owned(bytes: Vec<u8>) -> String {
+  match String::from_utf8_lossy(&bytes) {
+    Cow::Owned(code) => code,
+    // SAFETY: `String::from_utf8_lossy` guarantees that the result is valid
+    // UTF-8 if `Cow::Borrowed` is returned.
+    Cow::Borrowed(_) => unsafe { String::from_utf8_unchecked(bytes) },
+  }
+}
+
+#[inline(always)]
+pub fn from_utf8_lossy_cow(bytes: Cow<[u8]>) -> Cow<str> {
+  match bytes {
+    Cow::Borrowed(bytes) => String::from_utf8_lossy(bytes),
+    Cow::Owned(bytes) => Cow::Owned(from_utf8_lossy_owned(bytes)),
+  }
+}
+
+/// Converts an `Arc<str>` to an `Arc<[u8]>`.
+#[allow(dead_code)]
+pub fn arc_str_to_bytes(arc_str: Arc<str>) -> Arc<[u8]> {
+  let raw = Arc::into_raw(arc_str);
+  // SAFETY: This is safe because they have the same memory layout.
+  unsafe { Arc::from_raw(raw as *const [u8]) }
+}
+
+/// Converts an `Arc<u8>` to an `Arc<str>` if able.
+#[allow(dead_code)]
+pub fn arc_u8_to_arc_str(
+  arc_u8: Arc<[u8]>,
+) -> Result<Arc<str>, std::str::Utf8Error> {
+  // Check that the string is valid UTF-8.
+  std::str::from_utf8(&arc_u8)?;
+  // SAFETY: the string is valid UTF-8, and the layout Arc<[u8]> is the same as
+  // Arc<str>. This is proven by the From<Arc<str>> impl for Arc<[u8]> from the
+  // standard library.
+  Ok(unsafe {
+    std::mem::transmute::<std::sync::Arc<[u8]>, std::sync::Arc<str>>(arc_u8)
+  })
+}