Move libs/libvmbase/example/tests/ under tests/

Extract the test (which consists of a host Rust program running a full
payload) outside of the library into its own standalone directory.

No functional change intended.

Bug: 352458998
Test: m vmbase_example.integration_test
Change-Id: I367964ccbf85774545a78e442501321183f98ba3
diff --git a/TEST_MAPPING b/TEST_MAPPING
index fc88a59..2112125 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -144,7 +144,7 @@
       "path": "packages/modules/Virtualization/android/vm"
     },
     {
-      "path": "packages/modules/Virtualization/libs/libvmbase"
+      "path": "packages/modules/Virtualization/tests/vmbase_example"
     },
     {
       "path": "packages/modules/Virtualization/guest/zipfuse"