fixup! stream: update TextEncoderStream to align the latest spec

Author: cola119

lib/internal/webstreams/encoding.js

@@ -4,6 +4,7 @@ const {
   ObjectDefineProperties,
   Symbol,
   String,
+  StringPrototypeCharCodeAt,
   Uint8Array,
 } = primordials;
 
@@ -62,7 +63,7 @@ class TextEncoderStream {
         let finalChunk = '';
         for (let i = 0; i < chunk.length; i++) {
           const item = chunk[i];
-          const codeUnit = item.charCodeAt(0);
+          const codeUnit = StringPrototypeCharCodeAt(item, 0);
           if (this[kPendingHighSurrogate] !== null) {
             const highSurrogate = this[kPendingHighSurrogate];
             this[kPendingHighSurrogate] = null;