Add java_sdk_library enforcement flag verification

Raise build error when PRODUCT_ENFORCE_INTER_PARTITION_JAVA_SDK_LIBRARY
is true while BOARD_VNDK_VERSION is not set because
PRODUCT_ENFORCE_INTER_PARTITION_JAVA_SDK_LIBRARY doesn't have any
meaning in that case.

Test: m nothing
Bug: 168180538
Change-Id: Ied2f99763a7cce7674ad50867403a66b18968071