[JSC] Optimize padding of UnlinkedCodeBlock to shrink

[JSC] Optimize padding of UnlinkedCodeBlock to shrink
https://bugs.webkit.org/show_bug.cgi?id=187448

Reviewed by Saam Barati.

Source/JavaScriptCore:

We optimize the size of CodeType and TriState. And we arrange the layout of UnlinkedCodeBlock.
These optimizations reduce the size of UnlinkedCodeBlock from 304 to 288.

* bytecode/CodeType.h:
* bytecode/UnlinkedCodeBlock.cpp:
(JSC::UnlinkedCodeBlock::UnlinkedCodeBlock):
* bytecode/UnlinkedCodeBlock.h:
(JSC::UnlinkedCodeBlock::codeType const):
(JSC::UnlinkedCodeBlock::didOptimize const):
(JSC::UnlinkedCodeBlock::setDidOptimize):
* bytecode/VirtualRegister.h:

Source/WTF:

* wtf/TriState.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@233629 268f45cc-cd09-0410-ab3c-d52691b4dbfc