performance-metrics: Add vm_type to PerformanceTestOverrides

Add an optional vm_type field to PerformanceTestOverrides to
allow overriding the VM type at runtime. Include vm_type in
the Display output for override logging.

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

performance-metrics/src/main.rs

@@ -178,6 +178,7 @@ pub struct PerformanceTestOverrides {
     test_iterations: Option<u32>,
     test_timeout: Option<u32>,
     test_image_format: Option<ImageFormat>,
+    vm_type: GuestVmType,
 }
 
 impl fmt::Display for PerformanceTestOverrides {
@@ -193,6 +194,8 @@ impl fmt::Display for PerformanceTestOverrides {
             write!(f, "test_image_format = {test_image_format}")?;
         }
 
+        write!(f, "vm_type = {}", self.vm_type)?;
+
         Ok(())
     }
 }
@@ -1887,6 +1890,7 @@ fn main() {
             .map(|s| s.parse())
             .transpose()
             .unwrap_or_default(),
+        vm_type: GuestVmType::Regular,
     });
 
     // Skip heavy VM level init/cleanup when only micro benchmarks are selected.