Disable reflow when winptyCompat is on

Fixes #1943

src/Buffer.ts

@@ -211,7 +211,7 @@ export class Buffer implements IBuffer {
 
     this.scrollBottom = newRows - 1;
 
-    if (this._hasScrollback) {
+    if (this._isReflowEnabled) {
       this._reflow(newCols, newRows);
 
       // Trim the end of the line off if cols shrunk
@@ -226,6 +226,10 @@ export class Buffer implements IBuffer {
     this._rows = newRows;
   }
 
+  private get _isReflowEnabled(): boolean {
+    return this._hasScrollback && !(this._terminal as any).isWinptyCompatEnabled;
+  }
+
   private _reflow(newCols: number, newRows: number): void {
     if (this._cols === newCols) {
       return;