Move mini-lz4.js to third_party. NFC. (#12981)

See #12980

src/library_lz4.js

@@ -15,7 +15,7 @@ mergeInto(LibraryManager.library, {
     init: function() {
       if (LZ4.codec) return;
       LZ4.codec = (function() {
-        {{{ read('mini-lz4.js') }}};
+        {{{ read('../third_party/mini-lz4.js') }}};
         return MiniLZ4;
       })();
       LZ4.CHUNK_SIZE = LZ4.codec.CHUNK_SIZE;

tools/file_packager.py

@@ -508,7 +508,7 @@ def main():
       temp = data_target + '.orig'
       shutil.move(data_target, temp)
       meta = shared.run_js_tool(shared.path_from_root('tools', 'lz4-compress.js'),
-                                [shared.path_from_root('src', 'mini-lz4.js'),
+                                [shared.path_from_root('third_party', 'mini-lz4.js'),
                                 temp, data_target], stdout=PIPE)
       os.unlink(temp)
       use_data = '''