Fixes crash when calling twice HWCDC::end()

[SuGlider]

Description of Change

JTAG/CDC Serial interface crashes when Serial.end() is called twice.
This PR shall be applied to Arduino Core 2.0.10 and 3.0.0.

Tests scenarios

Tested with ESP32-C3 and ESP32-S3.

// MUST USE USB Mode "CDC/JTAG" and "CDC on Boot: Enabled" void setup() { // No need to initialize the RGB LED Serial.begin(); delay(500); Serial.println("First Print Testing"); Serial.flush(); Serial.end(); Serial.end(); // Second end() causes crash. Serial.begin(); log_d("LOG printing after end-begin"); Serial.println("Second Print Testing"); Serial.flush(); } void loop() { }

Related links

Fix #8326