Move HiddenApiTest from src to src/java

The java files have recently been moved to src/java in order to have
both java and native source files under src. However, HiddenApiTest.java
wasn't moved then. Fixing the error.

Test: atest  CtsHiddenApiDiscoveryTestCases The test runs.
Change-Id: Idcb1432071552e41611bce298a7ba876edb1be73
diff --git a/tests/signature/api-check/build_signature_apk.mk b/tests/signature/api-check/build_signature_apk.mk
index 1bae842..8eb8795 100644
--- a/tests/signature/api-check/build_signature_apk.mk
+++ b/tests/signature/api-check/build_signature_apk.mk
@@ -30,7 +30,7 @@
 
 LOCAL_STATIC_JAVA_LIBRARIES := cts-api-signature-test
 
-LOCAL_JNI_SHARED_LIBRARIES := libclassdescriptors
+LOCAL_JNI_SHARED_LIBRARIES += libclassdescriptors
 LOCAL_MULTILIB := both
 
 LOCAL_ADDITIONAL_DEPENDENCIES += \
diff --git a/tests/signature/api-check/hidden-api/Android.mk b/tests/signature/api-check/hidden-api/Android.mk
index 25df1bc..a5bc737 100644
--- a/tests/signature/api-check/hidden-api/Android.mk
+++ b/tests/signature/api-check/hidden-api/Android.mk
@@ -36,8 +36,6 @@
 include $(CLEAR_VARS)
 LOCAL_PACKAGE_NAME := CtsHiddenApiDiscoveryTestCases
 LOCAL_MODULE_PATH := $(TARGET_OUT_DATA_APPS)
-LOCAL_MULTILIB := both
 LOCAL_SIGNATURE_API_FILES := blacklist.api
 LOCAL_JNI_SHARED_LIBRARIES := libcts_hiddenapi
-LOCAL_NDK_STL_VARIANT := c++_static
 include $(LOCAL_PATH)/../build_signature_apk.mk
diff --git a/tests/signature/api-check/src/android/signature/cts/api/HiddenApiTest.java b/tests/signature/api-check/src/java/android/signature/cts/api/HiddenApiTest.java
similarity index 100%
rename from tests/signature/api-check/src/android/signature/cts/api/HiddenApiTest.java
rename to tests/signature/api-check/src/java/android/signature/cts/api/HiddenApiTest.java