RFR 8159850: Remove unneeded parsing of optional-size when parsing array types

[harold seigel]

Hi,

Please review this small JDK-11 change to fix JDK-8159850.  The fix 
removes the unneeded skip_optional_size() methods and the calls to them.

Open Webrev: 
http://cr.openjdk.java.net/~hseigel/bug_8159850/webrev/index.html

JBS Bug:  https://bugs.openjdk.java.net/browse/JDK-8159850

This change was tested with Mach5 tiers 1 and 2 tests and builds on all 
Mach5 platforms, with tiers 3-5 tests on Linux-x64, with JCK-10 Lang and 
VM tests, and with additional JDK JTReg tests.

Thanks, Harold