CVE-2020-15265: In Tensorflow before version 2.4.0, an attacker can pass an invalid `axis` value to `tf.quantization.quantize_and_dequan

In TensorFlow before version 2.4.0, an attacker can provide an invalid `axis` parameter (a setting that specifies which dimension of data to work with) to a quantization function, causing the program to access memory outside the bounds of an array, which crashes the system. The vulnerability exists because the code only uses DCHECK (a debug-only validation that is disabled in normal builds) rather than proper runtime validation.