Fix eval fail with empty string
Fix eval fail with empty string

Fixes #278

JerryScript-DCO-1.0-Signed-off-by: pius.lee pius.lee@samsung.com

dbatyai/jerryscript,yichoi/jerryscript,slaff/jerryscript,robertsipka/jerryscript,slaff/jerryscript,LeeHayun/jerryscript,yichoi/jerryscript,jerryscript-project/jerryscript,bzsolt/jerryscript,gabrielschulhof/jerryscript,glistening/jerryscript,gabrielschulhof/jerryscript,gabrielschulhof/jerryscript,LaszloLango/jerryscript,slaff/jerryscript,bsdelf/jerryscript,grgustaf/jerryscript,martijnthe/jerryscript,martijnthe/jerryscript,bzsolt/jerryscript,slaff/jerryscript,LaszloLango/jerryscript,robertsipka/jerryscript,glistening/jerryscript,robertsipka/jerryscript,loki04/jerryscript,bsdelf/jerryscript,dbatyai/jerryscript,slaff/jerryscript,jerryscript-project/jerryscript,grgustaf/jerryscript,jack60504/jerryscript,LeeHayun/jerryscript,loki04/jerryscript,bsdelf/jerryscript,tilmannOSG/jerryscript,yichoi/jerryscript,dbatyai/jerryscript,LaszloLango/jerryscript,robertsipka/jerryscript,yichoi/jerryscript,dbatyai/jerryscript,bsdelf/jerryscript,zherczeg/jerryscript,loki04/jerryscript,zherczeg/jerryscript,gabrielschulhof/jerryscript,jack60504/jerryscript,tilmannOSG/jerryscript,jack60504/jerryscript,jack60504/jerryscript,LeeHayun/jerryscript,akosthekiss/jerryscript,jack60504/jerryscript,akosthekiss/jerryscript,LaszloLango/jerryscript,zherczeg/jerryscript,akosthekiss/jerryscript,robertsipka/jerryscript,grgustaf/jerryscript,martijnthe/jerryscript,jack60504/jerryscript,yichoi/jerryscript,zherczeg/jerryscript,grgustaf/jerryscript,LeeHayun/jerryscript,bzsolt/jerryscript,dbatyai/jerryscript,jerryscript-project/jerryscript,glistening/jerryscript,martijnthe/jerryscript,jerryscript-project/jerryscript,loki04/jerryscript,martijnthe/jerryscript,bzsolt/jerryscript,akosthekiss/jerryscript,LeeHayun/jerryscript,bzsolt/jerryscript,tilmannOSG/jerryscript,grgustaf/jerryscript,glistening/jerryscript,grgustaf/jerryscript,robertsipka/jerryscript,zherczeg/jerryscript,glistening/jerryscript,gabrielschulhof/jerryscript,tilmannOSG/jerryscript,bsdelf/jerryscript,LaszloLango/jerryscript,loki04/jerryscript,bsdelf/jerryscript,glistening/jerryscript,jerryscript-project/jerryscript,akosthekiss/jerryscript,loki04/jerryscript,tilmannOSG/jerryscript,martijnthe/jerryscript