performance-metrics: Remove duplicate x86_64 FOCAL_IMAGE_NAME

Remove the local x86_64 FOCAL_IMAGE_NAME constant from
performance_tests.rs. The identical public constant from
test_infra is already available via wildcard import.

The aarch64 definition is kept as it differs from test_infra:
performance-metrics uses a specific image with the
'-update-tool' suffix.

Signed-off-by: Muminul Islam <muislam@microsoft.com>

Author: russell-islam

performance-metrics/src/performance_tests.rs

@@ -13,8 +13,6 @@ use thiserror::Error;
 
 use crate::{ImageFormat, PerformanceTestControl, PerformanceTestOverrides, mean};
 
-#[cfg(target_arch = "x86_64")]
-pub const FOCAL_IMAGE_NAME: &str = "focal-server-cloudimg-amd64-custom-20210609-0.raw";
 #[cfg(target_arch = "aarch64")]
 pub const FOCAL_IMAGE_NAME: &str = "focal-server-cloudimg-arm64-custom-20210929-0-update-tool.raw";