Xtensa ESP32: Need to spill registers to memory as the last dying action before switching to a new thread.

Fix context save logic when called in window ABI configuration. Add an IDLE stack.  Don't depend on the mystery stack received from the bootloader.

Xtensa ESP32: Need to clone some logic for syncrhonous context switch.  Window spill logic in the conmon restores logic is inappropriate in this context

BugFix:uart_ops_s portion of cdcacm will not be initalized with correct functions if CONFIG_SERIAL_DMA is lit.

C&P error from F7

BugFix:uart_ops_s portion of cdcacm will not be initalized with correct functions if CONFIG_SERIAL_DMA is lit.

    This fixes the issses in a C99 compatible way

Xtensa ESP32: Fixes a few issue with restoring registers on interrupt return, but there is still a problem