8079841: Buffer underflow with empty zip entry names
Summary: check for zero-length entry name before accessing "last" byte
Reviewed-by: sherman, martin
Error at <anonymous> (test/script/basic/JDK-8030809.js:33) at func (test/script/basic/JDK-8030809.js:32) at <program> (test/script/basic/JDK-8030809.js:38)