Since dd849ffc, _rodata_start label has been moved to a different
linker output section from where the TLS templates (.tdata, .tbss)
are located. Since link-time addresses of thread-local variables are
calculated relative to the section start address, this resulted in
incorrect calculation of THREADPTR/$tp registers.
Fix by introducing new linker label, _flash_rodata_start, which points
to the .flash.rodata output section where TLS variables are located,
and use it when calculating THREADPTR/$tp.
Also remove the hardcoded rodata section alignment for Xtensa targets.
Alignment of rodata can be affected by the user application, which is
the issue dd849ffc was fixing. To accommodate any possible alignment,
save it in a linker label (_flash_rodata_align) and then use when
calculating THREADPTR. Note that this is not required on RISC-V, since
this target doesn't use TPOFF.
Fixes issue with DPORT init task, this task uses minimum stack size and may not be
enough if stack smashing detection is set to Overall mode.
Also reworks the way we calculate minimum stack to allow for adding multiple
contributing factors.
Closes https://github.com/espressif/esp-idf/issues/6403
Unless the option for "assert and keep running" is enabled.
This means that silent asserts now work for FreeRTOS, and disabling asserts
now also disables them in FreeRTOS without needing a separate config change.
Related to https://github.com/espressif/esp-idf/issues/6306
Enable shared stack watchpoint for overflow detection
Enable unit tests:
* "test printf using shared buffer stack" for C3
* "Test vTaskDelayUntil" for S2
* "UART can do poll()" for C3
