refactor(ext/tls): Implement required functionality for later SNI support (#23686)

Precursor to #23236 

This implements the SNI features, but uses private symbols to avoid
exposing the functionality at this time. Note that to properly test this
feature, we need to add a way for `connectTls` to specify a hostname.
This is something that should be pushed into that API at a later time as
well.

```ts
Deno.test(
  { permissions: { net: true, read: true } },
  async function listenResolver() {
    let sniRequests = [];
    const listener = Deno.listenTls({
      hostname: "localhost",
      port: 0,
      [resolverSymbol]: (sni: string) => {
        sniRequests.push(sni);
        return {
          cert,
          key,
        };
      },
    });

    {
      const conn = await Deno.connectTls({
        hostname: "localhost",
        [serverNameSymbol]: "server-1",
        port: listener.addr.port,
      });
      const [_handshake, serverConn] = await Promise.all([
        conn.handshake(),
        listener.accept(),
      ]);
      conn.close();
      serverConn.close();
    }

    {
      const conn = await Deno.connectTls({
        hostname: "localhost",
        [serverNameSymbol]: "server-2",
        port: listener.addr.port,
      });
      const [_handshake, serverConn] = await Promise.all([
        conn.handshake(),
        listener.accept(),
      ]);
      conn.close();
      serverConn.close();
    }

    assertEquals(sniRequests, ["server-1", "server-2"]);
    listener.close();
  },
);
```

---------

Signed-off-by: Matt Mastracci <matthew@mastracci.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/tests/integration/js_unit_tests.rs b/tests/integration/js_unit_tests.rs
index 2bf78034e..cbae4a0b8 100644
--- a/tests/integration/js_unit_tests.rs
+++ b/tests/integration/js_unit_tests.rs
@@ -94,6 +94,7 @@ util::unit_test_factory!(
     text_encoding_test,
     timers_test,
     tls_test,
+    tls_sni_test,
     truncate_test,
     tty_color_test,
     tty_test,
@@ -129,7 +130,7 @@ fn js_unit_test(test: String) {
     .arg("--no-prompt");
 
   // TODO(mmastrac): it would be better to just load a test CA for all tests
-  let deno = if test == "websocket_test" {
+  let deno = if test == "websocket_test" || test == "tls_sni_test" {
     deno.arg("--unsafely-ignore-certificate-errors")
   } else {
     deno