Fix incorrect assert expression in lexer_check_property_modifier (#4569)
Fix incorrect assert expression in lexer_check_property_modifier (#4569)

In the lexer_check_property_modifier the assert incorrectly does
an assignment instead of a simple equals check.

JerryScript-DCO-1.0-Signed-off-by: Peter Gal pgal.usz@partner.samsung.com
zherczeg/jerryscript,zherczeg/jerryscript,bzsolt/jerryscript,jerryscript-project/jerryscript,dbatyai/jerryscript,robertsipka/jerryscript,bzsolt/jerryscript,zherczeg/jerryscript,jerryscript-project/jerryscript,robertsipka/jerryscript,dbatyai/jerryscript,dbatyai/jerryscript,dbatyai/jerryscript,bzsolt/jerryscript,robertsipka/jerryscript,zherczeg/jerryscript,bzsolt/jerryscript,jerryscript-project/jerryscript,bzsolt/jerryscript,zherczeg/jerryscript,robertsipka/jerryscript,robertsipka/jerryscript,dbatyai/jerryscript,robertsipka/jerryscript,jerryscript-project/jerryscript,jerryscript-project/jerryscript