Fix readBitsIntLe to use unsigned right bit shift

See kaitai-io/kaitai_struct_javascript_runtime@1f8dd95

Author: generalmimon

src/main/java/io/kaitai/struct/KaitaiStream.java

@@ -247,7 +247,7 @@ public long readBitsIntLe(int n) {
         // derive reading result
         long res = bits & mask;
         // remove bottom bits that we've just read by shifting
-        bits >>= n;
+        bits >>>= n;
         bitsLeft -= n;
 
         return res;