Remove ndk_platform backend. Use the ndk backend.

The ndk_platform backend will soon be deprecated because the ndk backend
can serve the same purpose. This is to eliminate the confusion about
having two variants (ndk and ndk_platform) for the same 'ndk' backend.

Bug: 161456198
Test: m
Change-Id: I3bcfc77e86a95b64ff80587c3d7f68be5b5100b8
diff --git a/tests/testapk/Android.bp b/tests/testapk/Android.bp
index 7332149..f545f8e 100644
--- a/tests/testapk/Android.bp
+++ b/tests/testapk/Android.bp
@@ -18,7 +18,7 @@
     name: "MicrodroidTestNativeLib",
     srcs: ["src/native/testbinary.cpp"],
     shared_libs: [
-        "android.system.keystore2-V1-ndk_platform",
+        "android.system.keystore2-V1-ndk",
         "libbase",
         "libbinder_ndk",
         "MicrodroidTestNativeLibSub",