minui: Fix a wrong arg in calling GRSurface::Create().

This is a bug introduced while refactoring init_display_surface(), in
[1]. As a result, user of res_create_multi_display_surface(), which is
effectively `charger` right now, crashes due to buffer overrun.

This CL fixes the wrong arg and adds a sanity test for
res_create_multi_display_surface(). The testdata (battery_scale.png) is
copied from system/core/healthd/images/battery_scale.png.

[1] commit 44820ac1e31ffa029ab5baa71238a11b6db3e6cc.

Bug: 119122296
Test: Run recovery_unit_test on marlin.
Test: Build and boot into charger mode on blueline. Verify that
      `charger` no longer crashes.
Change-Id: Ib6d083e1512a9c3c6eb63874d26d22658921d693
diff --git a/minui/resources.cpp b/minui/resources.cpp
index c7af190..057d3fd 100644
--- a/minui/resources.cpp
+++ b/minui/resources.cpp
@@ -261,7 +261,7 @@
   for (int i = 0; i < *frames; ++i) {
     auto height_per_frame = height / *frames;
     auto created_surface =
-        GRSurface::Create(width, height_per_frame, width * 4, 4, width * height_per_frame);
+        GRSurface::Create(width, height_per_frame, width * 4, 4, width * height_per_frame * 4);
     if (!created_surface) {
       result = -8;
       goto exit;