Add CL_DEVICE_NAME to clDeviceInfo File (#836)

- [x] Add `CL_DEVICE_NAME` to list of device properties printed into the
clDeviceInfo file for offline compilation testing.
- [x] Add `get_device_name` helper function.
- [x] Update offline compiler interface explanation file with
`CL_DEVICE_NAME` and `CL_DEVICE_IMAGE_SUPPORT` which was missed from
this file when added.

test_common/harness/deviceInfo.cpp

@@ -79,3 +79,9 @@ std::string get_device_version_string(cl_device_id device)
 {
     return get_device_info_string(device, CL_DEVICE_VERSION);
 }
+
+/* Returns a string containing the device name. */
+std::string get_device_name(cl_device_id device)
+{
+    return get_device_info_string(device, CL_DEVICE_NAME);
+}