perf(ext/node): improve `Buffer.from(buffer)` (#24352)

Benchmark code from #24341.

```shellsession
$ deno run --allow-hrtime bench.mjs
6479.111583
$ target/release/deno run --allow-hrtime bench.mjs
962.753875
$ node bench.mjs
855.174875
```

1 files changed, 7 insertions, 4 deletions

diff --git a/tests/unit_node/buffer_test.ts b/tests/unit_node/buffer_test.ts
index 0005b1b5d..07f5dd2c1 100644
--- a/tests/unit_node/buffer_test.ts
+++ b/tests/unit_node/buffer_test.ts
@@ -534,15 +534,18 @@ Deno.test({
 });
 
 Deno.test({
-  name: "[node/buffer] Buffer from another buffer creates a Buffer",
+  name: "[node/buffer] Buffer from another buffer creates a copy",
   fn() {
-    const buffer: Buffer = Buffer.from(Buffer.from("test"));
-    assertEquals(buffer.length, 4, "Buffer length should be 4");
+    const buffer1: Buffer = Buffer.from("test");
+    const buffer2: Buffer = Buffer.from(buffer1);
+    assertEquals(buffer2.length, 4, "Buffer length should be 4");
     assertEquals(
-      buffer.toString(),
+      buffer2.toString(),
       "test",
       "Buffer to string should recover the string",
     );
+    buffer1[0] = 114;
+    assertEquals(buffer2.toString(), "test", "Buffer should be a copy");
   },
 });