Add module `libopenjdk` to the Android Runtime APEX module.

This is so that we can remove it from `PRODUCT_PACKAGES`, i.e. no
longer install it on /system, as module `libopenjdk` depends on module
`libart`; the installation of the former would trigger the
installation of the latter, which we are trying to stop (see companion
change in project platform/build).

Also label `libopenjdkd` as a Libcore library in the Runtime APEX
definition.

Test: art/build/apex/runtests.sh
Test: Device boot test with Android Runtime APEX.
Bug: 113373927
Change-Id: I17a6dec4b7b4e813a6d55c4aafbad2e793bfd69d
diff --git a/build/apex/runtests.sh b/build/apex/runtests.sh
index 9db325a..b2aa4df 100755
--- a/build/apex/runtests.sh
+++ b/build/apex/runtests.sh
@@ -157,6 +157,7 @@
   check_library libprofile.so
   # Check that the mounted image contains Android Core libraries.
   check_library libjavacrypto.so
+  check_library libopenjdk.so
   # Check that the mounted image contains additional required libraries.
   check_library libadbconnection.so
 
@@ -193,11 +194,12 @@
   check_library libartd-dexlayout.so
   check_library libartd.so
   check_library libdexfiled.so
-  check_library libopenjdkd.so
   check_library libopenjdkjvmd.so
   check_library libopenjdkjvmtid.so
   check_library libprofiled.so
-  # Check that the mounted image contains additional required libraries.
+  # Check that the mounted image contains Android Core debug libraries.
+  check_library libopenjdkd.so
+  # Check that the mounted image contains additional required debug libraries.
   check_library libadbconnectiond.so
 }