Move JNI-based Parser to jni subpackage

Author: headius

…ain/java/org/ruby_lang/prism/Parser.java …java/org/ruby_lang/prism/jni/Parser.javajava/native/src/main/java/org/ruby_lang/prism/Parser.java renamed to java/native/src/main/java/org/ruby_lang/prism/jni/Parser.java java/native/src/main/java/org/ruby_lang/prism/Parser.java renamed to java/native/src/main/java/org/ruby_lang/prism/jni/Parser.java

@@ -1,4 +1,4 @@
-package org.ruby_lang.prism;
+package org.ruby_lang.prism.jni;
 
 public abstract class Parser {