Vulkan: Fix whitebox test to end render pass

Since the RAII-based GLRenderbuffer goes away at the end of the test
function, we should end the render pass before ending the test.

Bug: chromium:1122621
Change-Id: I5aaf2a0b4fd63a38fc5018830ee4e9d7d93f0c81
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2380248
Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Ian Elliott <ianelliott@google.com>
Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com>
Commit-Queue: Ian Elliott <ianelliott@google.com>

src/tests/gl_tests/VulkanPerformanceCounterTest.cpp

@@ -467,6 +467,11 @@ TEST_P(VulkanPerformanceCounterTest, InvalidatingAndUsingDepthDoesNotBreakRender
 
     uint32_t actualRenderPassCount = counters.renderPasses;
     EXPECT_EQ(expectedRenderPassCount, actualRenderPassCount);
+
+    // Make sure the render pass is ended by reading back a pixel.  Otherwise, the render pass will
+    // end when the test infrastructure calls eglSwapBuffers(), after the RAII-based GLRenderbuffer
+    // has been deleted.
+    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
 }
 
 // Tests that even if the app clears depth, it should be invalidated if there is no read.