Use sdkSpec to compare sdk_versions of APK/JNI

"current" is converted to int differently if we use
sdkSpec.effectiveVersion for APK and android.ApiStrToNum for JNI.
For example, in REL branch, "current" is equiv to PlatformSdkVersion
for APK, but 10000(FutureApiVersion) for JNI.

Use sdkSpec.effectiveVersion to compare APK.min_sdk_version and
JNI.sdk_version.

Bug: 145796956
Test: m
Change-Id: I2c4dbb79ae8712004dc3a9e647aa53cd5de7b508