computeinfo: fix memory leak

Even on the common code path (i.e., no error paths taken),
test_computeinfo failed to release its allocated memory, preventing a
clean run with LeakSanitizer.

Signed-off-by: Sven van Haastregt <sven.vanhaastregt@arm.com>

test_conformance/computeinfo/main.cpp

@@ -1452,5 +1452,9 @@ int main(int argc, const char** argv)
  }
  }
 
- return runTestHarness(argCount, argList, test_num, test_list, true, 0);
+ int error = runTestHarness(argCount, argList, test_num, test_list, true, 0);
+
+ free(argList);
+
+ return error;
 }