project: generic-arm-test-inc.mk: add rust user tests

Bug: 263261677
Change-Id: I5570abbb97870b7db69a5223b1e446a806d714f9
diff --git a/project/generic-arm-test-inc.mk b/project/generic-arm-test-inc.mk
index f5fe70e..27d8246 100644
--- a/project/generic-arm-test-inc.mk
+++ b/project/generic-arm-test-inc.mk
@@ -20,6 +20,7 @@
 include project/generic-arm-inc.mk
 include trusty/kernel/kerneltests-inc.mk
 include trusty/user/base/usertests-inc.mk
+include trusty/user/base/usertests-rust-inc.mk
 
 # Only enable pattern init in test-builds, as it has runtime overhead
 # and intentionally attempts to induce crashes for bad assumptions.