Make ParserError immutable by design

Make ParserError immutable by design
https://bugs.webkit.org/show_bug.cgi?id=141955

Reviewed by Geoffrey Garen.

This patch enforce that no field of ParserError can
be modified after the constructor.

* parser/ParserError.h:
Move the attributes to pack the integer + 2 bytes together.
This is irrelevant for memory impact, it is to remve a load-store
when copying by value.

Also move the attributes to be private.

(JSC::ParserError::isValid):
To client of the interface cared about the type of the error,
the only information needed was: is there an error.

(JSC::ParserError::ParserError):
(JSC::ParserError::syntaxErrorType):
(JSC::ParserError::token):
(JSC::ParserError::message):
(JSC::ParserError::line):
(JSC::ParserError::toErrorObject):
* API/JSScriptRef.cpp:
* builtins/BuiltinExecutables.cpp:
(JSC::BuiltinExecutables::createBuiltinExecutable):
* bytecode/UnlinkedCodeBlock.cpp:
(JSC::generateFunctionCodeBlock):
(JSC::UnlinkedFunctionExecutable::fromGlobalCode):
(JSC::UnlinkedFunctionExecutable::codeBlockFor):
* bytecode/UnlinkedCodeBlock.h:
* inspector/agents/InspectorRuntimeAgent.cpp:
(Inspector::InspectorRuntimeAgent::parse):
* jsc.cpp:
(runInteractive):
* parser/Parser.h:
(JSC::parse):
* runtime/CodeCache.cpp:
(JSC::CodeCache::getGlobalCodeBlock):
(JSC::CodeCache::getFunctionExecutableFromGlobalCode):
* runtime/CodeCache.h:
* runtime/Completion.h:
* runtime/Executable.cpp:
(JSC::ProgramExecutable::checkSyntax):
* runtime/JSGlobalObject.cpp:
(JSC::JSGlobalObject::createProgramCodeBlock):
(JSC::JSGlobalObject::createEvalCodeBlock):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@180637 268f45cc-cd09-0410-ab3c-d52691b4dbfc