[OpenCL] Fix typo in the test.

Author: Anastasia Stulova

clang/test/SemaOpenCL/func.cl

@@ -1,6 +1,6 @@
 // RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only -triple spir-unknown-unknown
 // RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only -triple spir-unknown-unknown -DFUNCPTREXT
-// RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only -triple spir-unknown-unknown -DVARARG
+// RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only -triple spir-unknown-unknown -DVARARGEXT
 
 #ifdef FUNCPTREXT
 #pragma OPENCL EXTENSION __cl_clang_function_pointers : enable