Revert "Increase max VM memory for CompOS"

This reverts commit 39da7697f097a9d0c4baadb5fc1683b67795c6df.

Reason for revert: didn't reduce the rate of OOM failures in tests.
Bug: 264496291

Change-Id: I177304f9124431590a31361a0a738b82b764175e
diff --git a/compos/composd/src/instance_manager.rs b/compos/composd/src/instance_manager.rs
index c4791e9..c3d6592 100644
--- a/compos/composd/src/instance_manager.rs
+++ b/compos/composd/src/instance_manager.rs
@@ -30,7 +30,7 @@
 use virtualizationservice::IVirtualizationService::IVirtualizationService;
 
 // Enough memory to complete odrefresh in the VM.
-const VM_MEMORY_MIB: i32 = 1280;
+const VM_MEMORY_MIB: i32 = 1024;
 
 pub struct InstanceManager {
     service: Strong<dyn IVirtualizationService>,