[sival,flash_counters] Change test counters from flash to retention sram

### Description

Flash based counters are not advisable in silicon. Replace them by the counters in ret_sram_testutils.
There are some tests that have already been changed. Be careful: unlike flash counters, the retention sram
counters must be initialized for each test. They are primarily used for tests that reset during execution, but
POR while running is not supported since ram contents are wiped out in that case.

There are a handful of sim_dv tests that use flash counters, and one in sw/device/silicon_creator/rom/e2e.