8356036: (fs) FileKey.hashCode and UnixFileStore.hashCode implementations can use Long.hashCode

Reviewed-by: liach, bpb

Author: wenshao

src/java.base/unix/classes/sun/nio/ch/FileKey.java

@@ -49,8 +49,7 @@ public static FileKey create(FileDescriptor fd) throws IOException {
 
     @Override
     public int hashCode() {
-        return (int)(st_dev ^ (st_dev >>> 32)) +
-               (int)(st_ino ^ (st_ino >>> 32));
+        return Long.hashCode(st_dev) + Long.hashCode(st_ino);
     }
 
     @Override

src/java.base/unix/classes/sun/nio/fs/UnixFileKey.java

@@ -40,8 +40,7 @@ class UnixFileKey {
 
     @Override
     public int hashCode() {
-        return (int)(st_dev ^ (st_dev >>> 32)) +
-               (int)(st_ino ^ (st_ino >>> 32));
+        return Long.hashCode(st_dev) + Long.hashCode(st_ino);
     }
 
     @Override

src/java.base/unix/classes/sun/nio/fs/UnixFileStore.java

@@ -241,7 +241,7 @@ public boolean equals(Object ob) {
 
     @Override
     public int hashCode() {
-        return (int)(dev ^ (dev >>> 32)) ^ Arrays.hashCode(entry.dir());
+        return Long.hashCode(dev) ^ Arrays.hashCode(entry.dir());
     }
 
     @Override