Even after commit 0b47c126
there are a few ib::fatal() calls in non-debug code
that can be replaced easily.

btr_page_reorganize_low(): On size invariant violation, return
an error code instead of crashing.

btr_check_blob_fil_page_type(): On an invalid page type, report
an error but do not crash.

btr_copy_blob_prefix(): Truncate the output if a page type is invalid.

dict_load_foreign_cols(): On an error, return DB_CORRUPTION instead
of crashing.

fil_space_decrypt_full_crc32(), fil_space_decrypt_for_non_full_checksum():
On error, return DB_DECRYPTION_FAILED instead of crashing.

fil_set_max_space_id_if_bigger(): Replace ib::fatal() with an
equivalent ut_a() assertion.