Don't reallocate EGLSurface for same debug surface.

Recreating an EGLSurface for a surface that already has an
EGLSurface is not allowed according to the
[documentation](https://www.khronos.org/registry/EGL/sdk/docs/man/html/eglCreatePlatformWindowSurface.xhtml).

This fix was tested on the devices listed in the bug
description (Pixel 5a, Nexus 5).

PiperOrigin-RevId: 450473569

library/transformer/src/main/java/com/google/android/exoplayer2/transformer/FrameProcessorChain.java

@@ -602,10 +602,13 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     @Override
     @Override
     public synchronized void surfaceChanged(
     public synchronized void surfaceChanged(
         SurfaceHolder holder, int format, int width, int height) {
         SurfaceHolder holder, int format, int width, int height) {
-      surface = holder.getSurface();
-      eglSurface = null;
       this.width = width;
       this.width = width;
       this.height = height;
       this.height = height;
+      Surface newSurface = holder.getSurface();
+      if (surface == null || !surface.equals(newSurface)) {
+        surface = newSurface;
+        eglSurface = null;
+      }
     }
     }
 
 
     @Override
     @Override