CTS: Encrypted storage is inaccessible to diff VM

Test that encrypted storage of 1 pVM should not be accessible by a VM
with different identity.

Well not really.. The storage image of pvm1 (atleast after first boot)
contains encrypted filesystem which should mean nothing more than random
garbage when a different VM tries to access it. encryptedstore will fail
to 'mount' this filesystem.

This is equivalent to testing that sealing key derived for a different
instance image is different.

Test: #encryptedStorageIsInaccessibleToDiffVm
Bug: 259233794
Change-Id: I54cc84d7e1a5949879dd9bc7268d3a0e801c7649
diff --git a/encryptedstore/src/main.rs b/encryptedstore/src/main.rs
index 2f54534..96c80db 100644
--- a/encryptedstore/src/main.rs
+++ b/encryptedstore/src/main.rs
@@ -46,6 +46,7 @@
     let blkdevice = Path::new(matches.get_one::<String>("blkdevice").unwrap());
     let key = matches.get_one::<String>("key").unwrap();
     let mountpoint = Path::new(matches.get_one::<String>("mountpoint").unwrap());
+    // Note this error context is used in MicrodroidTests.
     encryptedstore_init(blkdevice, key, mountpoint).context(format!(
         "Unable to initialize encryptedstore on {:?} & mount at {:?}",
         blkdevice, mountpoint