phpMyAdmin hangs on LOCK TABLES statement with MySQL 5.7

Describe the bug

Cannot execute standard MySQL 5.7 database dump script in PMA because of it contains LOCK/UNLOCK TABLES statements.

To Reproduce

1. Use PMA 4.8.5. Login to MySQL 5.7 server and create/choose a clean database.
2. Go to SQL tab and copy SQL script from attachment:
   sql.txt
3. Click Go.
4. See that:
   A. PMA hangs.
   B. MySQL server eats about 50% CPU.
   C. If you try close PMA and open again it hangs.
   D. Restart of MySQL server can help you only.

Expected behavior

User can execute SQL scripts with LOCK/UNLOCK TABLES statements on MySQL 5.7 and any other version.

Screenshots

Server configuration

• Operating system:

OS Name: Microsoft Windows Server 2016 Datacenter
OS Version: 10.0.14393 N/A Build 14393
or
OS Name: Microsoft Windows Server 2008 R2 Enterprise
OS Version: 6.1.7601 Service Pack 1 Build 7601

• Web server:

Microsoft-IIS/10.0 or Microsoft-IIS/7.5

• Database version:

5.7.25 - MySQL Community Server

• PHP version:

7.1.14 or 7.3.3

• phpMyAdmin version:

4.8.5 or 4.8.4

Client configuration

• Browser:

IE 11 or Firefox 66

• Operating system:

OS Name: Microsoft Windows Server 2016 Datacenter
OS Version: 10.0.14393 N/A Build 14393
or
OS Name: Microsoft Windows Server 2008 R2 Enterprise
OS Version: 6.1.7601 Service Pack 1 Build 7601

Additional context

my.ini settings:

[MySQLD]
port=3306
basedir=...
datadir=...
character-set-server=latin1
default-storage-engine=INNODB
read_buffer_size=1M
read_rnd_buffer_size=256K
sort_buffer_size=256K
innodb_flush_log_at_trx_commit=1
innodb_log_buffer_size=1M
innodb_buffer_pool_size=16M
innodb_log_file_size=10M
innodb_thread_concurrency=8
max_connections=151
old_passwords=0
max_user_connections=30
thread_cache_size=4
thread_stack=196608
binlog_cache_size=32768
net_read_timeout=30
net_retry_count=10
net_write_timeout=30
open_files_limit=4161
table_definition_cache=400
[client]
port=3306

Start by reproducing the issue from the attached sql.txt through the SQL tab against MySQL 5.7, including the LOCK/UNLOCK TABLES statements. Trace the SQL execution path involved in the hang and verify that the script completes without PMA or MySQL becoming unresponsive.