During coredump, dangerous-area-checking should be disabled, and cache
disabling should be replaced by a safer version.
Dangerous-area-checking used to be in the HAL, but it seems to be more
fit to os functions. So it's moved to os functions. Interfaces are
provided to switch between os functions during coredump.
When legacy mode is used, the coredump still fails during linking
because "esp_flash_init_default_chip", "esp_flash_app_init" and
"esp_flash_default_chip " are not compiled and linked.
Instead of using ``if`` macros in callers, these functions are protected
by ``if`` macros in the header, and also not compiled in the sources.
"esp_flash_default_chip" variable is compiled with safe default value.
Michael (XIAO Xufeng)