MDEV-36373 Bogus Warning: ... storage is corrupted

ha_innobase::statistics_init(), ha_innobase::info_low():
Correctly handle a DB_READ_ONLY return value from dict_stats_save().
Fixes up commit 6e6a1b316c (MDEV-35000)

mysql-test/suite/innodb/r/stat_tables.result

@@ -101,3 +101,13 @@ DROP TABLE t1;
 CREATE TABLE t1 (c1 INT) ENGINE=InnoDB STATS_PERSISTENT 1;
 DROP TABLE t1;
 # End of 10.6 tests
+#
+# MDEV-36373 Warning: ... persistent statistics storage is corrupted
+#
+CREATE TABLE t1 (c INT) ENGINE=InnoDB;
+SET STATEMENT tx_read_only=1 FOR ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+DROP TABLE t1;
+# End of 10.11 tests

mysql-test/suite/innodb/t/stat_tables.test

@@ -110,3 +110,12 @@ CREATE TABLE t1 (c1 INT) ENGINE=InnoDB STATS_PERSISTENT 1;
 DROP TABLE t1;
 
 --echo # End of 10.6 tests
+
+--echo #
+--echo # MDEV-36373 Warning: ... persistent statistics storage is corrupted
+--echo #
+CREATE TABLE t1 (c INT) ENGINE=InnoDB;
+SET STATEMENT tx_read_only=1 FOR ANALYZE TABLE t1;
+DROP TABLE t1;
+
+--echo # End of 10.11 tests

storage/innobase/handler/ha_innodb.cc

@@ -5872,7 +5872,7 @@ dberr_t ha_innobase::statistics_init(dict_table_t *table, bool recalc)
           if (err == DB_STATS_DO_NOT_EXIST && table->stats_is_auto_recalc())
             goto recalc;
         }
-        if (err == DB_SUCCESS)
+        if (err == DB_SUCCESS || err == DB_READ_ONLY)
           return err;
         if (!recalc)
           break;
@@ -14934,6 +14934,7 @@ recalc:
 				ret = statistics_init(ib_table, is_analyze);
 				switch (ret) {
 				case DB_SUCCESS:
+				case DB_READ_ONLY:
 					break;
 				default:
 					goto error;