[avb][test] Move test util methods to a separate module

Bug: 256148034
Test: atest libpvmfw_avb.integration_test
Change-Id: Ibd24eadd1d8d8d6007dab9f63a28c963790a8563
diff --git a/pvmfw/avb/Android.bp b/pvmfw/avb/Android.bp
index 0527dfb..837f747 100644
--- a/pvmfw/avb/Android.bp
+++ b/pvmfw/avb/Android.bp
@@ -27,7 +27,7 @@
 rust_test {
     name: "libpvmfw_avb.integration_test",
     crate_name: "pvmfw_avb_test",
-    srcs: ["tests/*_test.rs"],
+    srcs: ["tests/*.rs"],
     test_suites: ["general-tests"],
     data: [
         ":avb_testkey_rsa2048_pub_bin",