Renames DestroyApiObject* to Destroy* for simplicity.

- Also updates and adds tests for CommandBuffer since it is the last object with a Destroy name clash.

Bug: dawn:628
Change-Id: I028e0101a91a785aa90d2b656556d48fe0d6e736
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/68101
Commit-Queue: Loko Kung <lokokung@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>

src/dawn_native/opengl/RenderPipelineGL.cpp

diff --git a/src/dawn_native/opengl/RenderPipelineGL.cpp b/src/dawn_native/opengl/RenderPipelineGL.cpp
index 7a56927..2f8e372 100644
--- a/src/dawn_native/opengl/RenderPipelineGL.cpp
+++ b/src/dawn_native/opengl/RenderPipelineGL.cpp
@@ -236,7 +236,7 @@
 
     RenderPipeline::~RenderPipeline() = default;
 
-    void RenderPipeline::DestroyApiObjectImpl() {
+    void RenderPipeline::DestroyImpl() {
         const OpenGLFunctions& gl = ToBackend(GetDevice())->gl;
         gl.DeleteVertexArrays(1, &mVertexArrayObject);
         gl.BindVertexArray(0);