Specify jnilib partition in Android-<target>.mk

Context
- Android-<target>.mk currently does not contain information about partition for its dependent unembedded jni libraries, but only lists the name of the unembedded jni libraries.
- If an android_app module depends on an unembedded jni library that is located in a different partition, make cannot find the library.

Implementation
- Create a string field partition in jniLib struct.
- Add variable "LOCAL_SOONG_JNI_LIBS_PARTITION_<target>", an array of mappings of the name of the jni library to its partition.

Bug: 154162945
Test: m
Change-Id: I6b8e1272ff59dc70e3dd6ce8c6c8e4686dad76df

java/java.go

@@ -418,6 +418,7 @@ type jniLib struct {
 	target         android.Target
 	coverageFile   android.OptionalPath
 	unstrippedFile android.Path
+	partition      string
 }
 
 func sdkDeps(ctx android.BottomUpMutatorContext, sdkContext android.SdkContext, d dexer) {