Apply clang format for samples files (#833)

Apply clang format for c source files under samples folder

samples/spawn-thread/wasm-apps/sum.c

@@ -3,7 +3,8 @@
  * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  */
 
-int sum(int start, int length)
+int
+sum(int start, int length)
 {
     int sum = 0, i;