analyzer: fix i18n issues in symbolic out-of-bounds [PR106626]

analyzer: fix i18n issues in symbolic out-of-bounds [PR106626]

gcc/analyzer/ChangeLog:
	PR analyzer/106626
	* bounds-checking.cc
	(symbolic_past_the_end::describe_final_event): Delete, moving to
	symbolic_buffer_overflow::describe_final_event and
	symbolic_buffer_over_read::describe_final_event, eliminating
	composition of text strings via "byte_str" and "m_dir_str".
	(symbolic_past_the_end::m_dir_str): Delete field.
	(symbolic_buffer_overflow::symbolic_buffer_overflow): Drop
	m_dir_str.
	(symbolic_buffer_overflow::describe_final_event): New, as noted
	above.
	(symbolic_buffer_over_read::symbolic_buffer_overflow): Drop
	m_dir_str.
	(symbolic_buffer_over_read::describe_final_event): New, as noted
	above.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>