Only add indexed BLOBs to row_ext.
trx_undo_rec_get_partial_row(): Move the BLOB fetching to row_ext_create().
row_build(): Pass only those BLOBs to row_ext_create() that are referenced by
ordering columns of some indexes, similar to trx_undo_rec_get_partial_row().
row_ext_create(): Add the parameter "tuple". Move the implementation
from row0ext.ic to row0ext.c.
row_ext_lookup_ith(), row_ext_lookup(): Return a const pointer. Remove
the parameters "field" and "f_len". Make the row_ext_t* parameter const.
row_ext_t: Remove the field zip_size.
field_ref_zero[]: Declare in btr0types.h instead of btr0cur.h.
row_ext_lookup_low(): Rename to row_ext_cache_fill() and change the
signature.
BLOB pointers, trx_id, and roll_ptr.
btr_empty(), btr_create(), page_create(): Add parameter "index", as some
index information will be encoded on the compressed page.
Define REC_NODE_PTR_SIZE as 4.
Allow btr_page_reorganize() and btr_page_reorganize_low() to fail.
Define the error code DB_ZIP_OVERFLOW.
Make row_ins_index_entry_low() static.
page0zip: Encode the index, log reorganized records, and store uncompressed
fields separately from the compressed data stream.
