kernel32/tests: Fix header comments.

dlls/kernel32/tests/process.c

 /*
- * Unit test suite for CreateProcess function.
+ * Unit test suite for process functions
  *
  * Copyright 2002 Eric Pouech
  * Copyright 2006 Dmitry Timoshkov

dlls/kernel32/tests/resource.c

 /*
- * Unit test suite for environment functions.
+ * Unit test suite for resource functions.
  *
  * Copyright 2006 Mike McCormack
  *

dlls/kernel32/tests/thread.c

 /*
- * Unit test suite for directory functions.
+ * Unit test suite for thread functions.
  *
  * Copyright 2002 Geoffrey Hausheer
  *

dlls/kernel32/tests/timer.c

 /*
- * Unit test suite for time functions
+ * Unit test suite for timer functions
  *
  * Copyright 2004 Mike McCormack
  *

dlls/kernel32/tests/volume.c

 /*
- * Unit test suite
+ * Unit test suite for volume functions
  *
  * Copyright 2006 Stefan Leichter
  *