Update on "[ET-VK][ez] Test command buffer re-encoding on resize"

## Context

Add a test where `encode_execute()` is called again after resizing model inputs and propagating the new sizes.

Currently, dynamic shapes are handled by simply updating the tensor metadata when sizes are updated. Compute shaders will perform the same computations with the updated tensor sizes/strides information.

However, for some operators, different input sizes require different compute shaders in order to achieve maximum performance. One example of this is for matrix multiplication, where matrix-matrix multiplication typically uses a different algorithm than vector-matrix (or matrix-vector) multiplication.

Therefore, for some models, it would be best to trigger a re-encoding of the command buffer upon input resize, so that different compute shaders can be selected based on the current input sizes.

The actual changes for enabling shader re-selection will be introduced in the next diff. This diff simply checks that command buffer re-encoding "works as advertised".

## Changes

This diff simply adds a test in `vulkan_compute_api_test` to test whether the ComputeGraph API can handle the `encode_execute` function  being called multiple times.

Differential Revision: [D75013781](https://our.internmc.facebook.com/intern/diff/D75013781/)

[ghstack-poisoned]

Author: SS-JIA