odh2: enable random odh1/odh2 by default for testing (DO NOT MERGE)

Test-only sub-branch: default to time-based genids + odh2 attr off + randomize_odh2
on, so a plain `make` in tests/ produces a mix of odh1 and odh2 records without a
CUSTOMLRLPATH fragment.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Mark Hannum <mhannum@bloomberg.net>

Author: markhannum

db/comdb2.c

@@ -382,7 +382,7 @@ int gbl_init_single_meta = 1;
 int gbl_schedule = 0;
 
 int gbl_init_with_rowlocks = 0;
-int gbl_init_with_genid48 = 1;
+int gbl_init_with_genid48 = 0; /* TEST BRANCH: time-based genids so odh1 is legal */
 int gbl_init_with_odh = 1;
 int gbl_init_with_queue_odh = 1;
 int gbl_init_with_queue_compr = BDB_COMPRESS_LZ4;
@@ -393,13 +393,13 @@ int gbl_init_with_instant_sc = 1;
  * (see legacy_options[] in config.c).  It is also forced at write time when the
  * db is in genid48 format, regardless of this default (a genid48 record must
  * never be odh1, or its insert time would be lost). */
-int gbl_init_with_odh2 = 1;
+int gbl_init_with_odh2 = 0; /* TEST BRANCH: baseline odh1 so the randomizer has something to flip */
 /* Test/debug only: when set, writes randomly UPGRADE records from odh1 to odh2
  * (never downgrade) while genids are time-based, so a single table ends up with
  * a mix of both header formats.  Off in normal operation; enable it to run the
  * test suite as an odh1/odh2 coexistence fuzzer.  Has no effect under genid48
  * (those writes are already forced to odh2). */
-int gbl_randomize_odh2 = 0;
+int gbl_randomize_odh2 = 1; /* TEST BRANCH: randomly write odh1/odh2 per record */
 /* Count of records the randomizer above emitted as odh2 (approximate -- bumped
  * without locking; lets a fuzz run confirm coexistence was actually produced). */
 int gbl_odh2_random_upgrades = 0;