Refactor VTS tests a bit, to enable adding tests in separate files.

Bug: 70409878
Test: VtsHalKeymasterV4_0TargetTest
Change-Id: Idd147d20761e7123005b468841a2ddb46cc19576
diff --git a/keymaster/4.0/vts/functional/Android.bp b/keymaster/4.0/vts/functional/Android.bp
index 3c3063c..fc6941f 100644
--- a/keymaster/4.0/vts/functional/Android.bp
+++ b/keymaster/4.0/vts/functional/Android.bp
@@ -18,6 +18,7 @@
     name: "VtsHalKeymasterV4_0TargetTest",
     defaults: ["VtsHalTargetTestDefaults"],
     srcs: [
+        "KeymasterHidlTest.cpp",
         "keymaster_hidl_hal_test.cpp",
     ],
     static_libs: [