pytest_panic used to do 'from conftest import PanicTestDut'. This
stopped working when another conftest.py file was added in
tools/test_build_system/conftest.py.
In this case we can't rename conftest.py since both are necessary
for pytest to install the hooks in the respective test cases.
Fix by moving PanicTestDut into a separate module, then importing
it from there.
Theory is that on the runner, in rare cases, gdb may need more than
1 second to load and start responding to commands.
However it's possible these timeouts are due to some other problem
(like gdb failing)
Small quality-of-life improvement, make it easier to run specific
test cases, when debugging the tests locally.
Take the optional list of test cases to run from the command line.
InstrFetchProhibited usually occurs because of a jump to an invalid
pointer. In this case, PC in the exception frame is the address of
the jump destination. 'esp_ptr_executable' check in print_backtrace
function recognizes the first frame as invalid, and the backtrace is
interrupted. This prevents the user from finding the location where
the invalid pointer is dereferenced.
Bypass the 'esp_ptr_executable' check if the exception cause is
InstrFetchProhibited. Update the test case to no longer ignore this
issue.
