Tests/IncludeDirectories: Files must end in a newline (#13314)

The HP compiler really really wants source files to end with a newline.

Tests/IncludeDirectories/TargetIncludeDirectories/CMakeLists.txt

@@ -5,9 +5,7 @@ project(TargetIncludeDirectories)
 
 macro(create_header _name)
   file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/${_name}")
-  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/${_name}/${_name}.h"
-  "//${_name}.h
-  ")
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/${_name}/${_name}.h" "//${_name}.h\n")
 endmacro()
 
 create_header(bar)