repl: Don't accumulate excess indentation in .load

When using .load the REPL would accumulate indentation with each line
including the indentation from all previous lines. Now it keeps the
indentation at the correct level.

Fixes: nodejs#47673

lib/repl.js

@@ -882,7 +882,7 @@ function REPLServer(prompt,
       self[kBufferedCommandSymbol] += cmd + '\n';
 
       // code alignment
-      const matches = self._sawKeyPress ?
+      const matches = self._sawKeyPress && !self._loading ?
         RegExpPrototypeExec(/^\s+/, cmd) : null;
       if (matches) {
         const prefix = matches[0];
@@ -1801,8 +1801,10 @@ function defineDefaultCommands(repl) {
         const stats = fs.statSync(file);
         if (stats && stats.isFile()) {
           _turnOnEditorMode(this);
+          this._loading = true;
           const data = fs.readFileSync(file, 'utf8');
           this.write(data);
+          this._loading = false;
           _turnOffEditorMode(this);
           this.write('\n');
         } else {