Move libdlext_... to NATIVE_TESTS instead of ETC

ETC did end up causing problems, since it's not per-arch. But
SHARED_LIBRARIES isn't correct either, since the build system tries to
read shared libraries as ELF files (to create the toc files).

NATIVE_TESTS is slightly better -- they are not libraries, so we don't
attempt to generate toc files, but they are considered per-arch.

Bug: 38463793
Test: Run CtsBionicTestCases
Change-Id: I01b4b093359e0c39eb2f8639d5c5dde9e304ed20
diff --git a/tests/libs/Android.build.dlext_testzip.mk b/tests/libs/Android.build.dlext_testzip.mk
index 0220ae2..4b6d099 100644
--- a/tests/libs/Android.build.dlext_testzip.mk
+++ b/tests/libs/Android.build.dlext_testzip.mk
@@ -22,7 +22,7 @@
 
 include $(CLEAR_VARS)
 
-LOCAL_MODULE_CLASS := ETC
+LOCAL_MODULE_CLASS := NATIVE_TESTS
 LOCAL_MODULE := libdlext_test_zip_zipaligned
 LOCAL_MODULE_SUFFIX := .zip
 LOCAL_MODULE_PATH := $($(bionic_2nd_arch_prefix)TARGET_OUT_DATA_NATIVE_TESTS)/bionic-loader-test-libs/libdlext_test_zip
@@ -44,7 +44,7 @@
 
 include $(CLEAR_VARS)
 
-LOCAL_MODULE_CLASS := ETC
+LOCAL_MODULE_CLASS := NATIVE_TESTS
 LOCAL_MODULE := libdlext_test_runpath_zip_zipaligned
 LOCAL_MODULE_SUFFIX := .zip
 LOCAL_MODULE_PATH := $($(bionic_2nd_arch_prefix)TARGET_OUT_DATA_NATIVE_TESTS)/bionic-loader-test-libs/libdlext_test_runpath_zip