Make rocksdb.use_direct_reads_writes more robust

Upstream commit ID : None
PS-7921 : Merge percona-202105

Summary:

Use an exclusive name for the log error file so concurrent executions of
the test don't try to use the same file.

mysql-test/suite/rocksdb/r/use_direct_reads_writes.result

@@ -1,5 +1,5 @@
-# restart:--log-error=MYSQLTEST_VARDIR/tmp/rocksdb.use_direct_reads_writes.err --rocksdb_use_direct_reads=1 --rocksdb_allow_mmap_reads=1
+# restart:--log-error=LOG_ERROR_FILE --rocksdb_use_direct_reads=1 --rocksdb_allow_mmap_reads=1
 Pattern "enable both use_direct_reads" found
-# restart:--log-error=MYSQLTEST_VARDIR/tmp/rocksdb.use_direct_reads_writes.err --rocksdb_use_direct_io_for_flush_and_compaction=1 --rocksdb_allow_mmap_writes=1
+# restart:--log-error=LOG_ERROR_FILE --rocksdb_use_direct_io_for_flush_and_compaction=1 --rocksdb_allow_mmap_writes=1
 Pattern "enable both use_direct_io_for_flush_and_compaction" found
 # restart

mysql-test/suite/rocksdb/t/use_direct_reads_writes.test

@@ -6,11 +6,12 @@
 # caused an assertion in RocksDB.  Now it should not be allowed and the
 # plugin will not initialize with that configuration
 
---let SEARCH_FILE=$MYSQLTEST_VARDIR/tmp/rocksdb.use_direct_reads_writes.err
+--let $FILE_ID = `SELECT uuid()`
+--let SEARCH_FILE=$MYSQLTEST_VARDIR/tmp/rocksdb.use_direct_reads_writes_$FILE_ID.err
 
 # Expect MyRocks to fail to initialize with invalid combination of arguments
 --let $restart_parameters=restart:--log-error=$SEARCH_FILE --rocksdb_use_direct_reads=1 --rocksdb_allow_mmap_reads=1
---replace_result $MYSQLTEST_VARDIR MYSQLTEST_VARDIR
+--replace_result $SEARCH_FILE LOG_ERROR_FILE
 --source include/restart_mysqld.inc
 
 # We should now have an error message
@@ -19,7 +20,7 @@
 
 # Repeat with --rocksdb-use-direct-writes
 --let $restart_parameters=restart:--log-error=$SEARCH_FILE --rocksdb_use_direct_io_for_flush_and_compaction=1 --rocksdb_allow_mmap_writes=1
---replace_result $MYSQLTEST_VARDIR MYSQLTEST_VARDIR
+--replace_result $SEARCH_FILE LOG_ERROR_FILE
 --source include/restart_mysqld.inc
 
 # We should now have an error message