frameworks/base: Set LOCAL_SDK_VERSION where possible.

This change sets LOCAL_SDK_VERSION for all packages where
this is possible without breaking the build, and
LOCAL_PRIVATE_PLATFORM_APIS := true otherwise.

Setting one of these two will be made required soon, and this
is a change in preparation for that. Not setting LOCAL_SDK_VERSION
makes the app implicitly depend on the bootclasspath, which is
often not required. This change effectively makes depending on
private apis opt-in rather than opt-out.

Test: make relevant packages
Bug: 73535841
Change-Id: I4233b9091d9066c4fa69f3d24aaf367ea500f760
diff --git a/tests/UsageStatsTest/Android.mk b/tests/UsageStatsTest/Android.mk
index 6b5c999..6735c7c 100644
--- a/tests/UsageStatsTest/Android.mk
+++ b/tests/UsageStatsTest/Android.mk
@@ -11,5 +11,6 @@
 LOCAL_CERTIFICATE := platform
 
 LOCAL_PACKAGE_NAME := UsageStatsTest
+LOCAL_PRIVATE_PLATFORM_APIS := true
 
 include $(BUILD_PACKAGE)