This specifically aims to test features that are not likely to occur
in normal operation, such as exceptions. Hits quite a few potential
corner cases but some are best tested in bare metal assembly and can't
be easily tested in an RTOS tests.

Co-authored-by: Nathaniel Filardo <[email protected]>

The static casts in the pointer DebugFormatArgumentAdapters prevented
function pointers from being printed as the compiler does not permit
static casts from function pointer to void*. Removing them seems to
work fine so not sure what they were there for.

Still some TODOs to resolve.

… review.

Also address a few other review comments.

behaviour

The previous approch no longer worked because the compiler would
choose a non-ra return register for the jalr, which means the return
register is no longer sealed, so remove the asm hack and use a helper
that uses __builtin_return_address. This new version is much cleaner
anyway.

It must return int so that test-runner can detect unintended faults / unwinds.

This allows us to continue even if we don't know where the faulting instruction is (for example after triggering a bounds fault on cjalr).

As Wes points out they do not necessarily fault so rename them to the
more neutral perform_load / perform_store.

It's good to check that memory wasn't modified in faulting cases and we stored the expected data in non-faulting cases.
One of the tests is redundant after an ISA change: it makes no difference whether the tag of a local capability being stored is set because it should will be cleared anyway.
Previously it would fault only if the tag was set.