When parsing a html fragment, the initial parser state depends on
whether or not scripting is enabled. So far we've used the scripting
flag of the parser, but that is wrong - the parser's scripting flag is
always false, because the fragment document has no browsing context.
Instead we should use the scripting flag of the context element.
Testing: A new web platform test passes
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Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>