Rename cl_intel_thread_local_exec to cl_intel_exec_by_local_thread (#716)

cl_intel_exec_by_local_thread is the correct extension name.

Author: fzou1

xml/cl.xml

@@ -5560,7 +5560,7 @@ server's OpenCL/api-docs repository.
                 <enum name="CL_DEVICE_COMPUTE_UNITS_BITFIELD_ARM"/>
             </require>
         </extension>
-        <extension name="cl_intel_thread_local_exec" supported="opencl">
+        <extension name="cl_intel_exec_by_local_thread" supported="opencl">
             <require>
                 <type name="CL/cl.h"/>
                 <type name="CL/cl_platform.h"/>