Remove writeUtf8 deprecated API

src/browser/TestUtils.test.ts

@@ -137,9 +137,6 @@ export class MockTerminal implements ITerminal {
   public write(data: string): void {
     throw new Error('Method not implemented.');
   }
-  public writeUtf8(data: Uint8Array): void {
-    throw new Error('Method not implemented.');
-  }
   public bracketedPasteMode!: boolean;
   public renderer!: IRenderer;
   public linkifier2!: ILinkifier2;

src/browser/public/Terminal.ts

@@ -219,9 +219,6 @@ export class Terminal implements ITerminalApi {
   public write(data: string | Uint8Array, callback?: () => void): void {
     this._core.write(data, callback);
   }
-  public writeUtf8(data: Uint8Array, callback?: () => void): void {
-    this._core.write(data, callback);
-  }
   public writeln(data: string | Uint8Array, callback?: () => void): void {
     this._core.write(data);
     this._core.write('\r\n', callback);