LibWeb: Break friendship between CSS Block and Parser

This means deviating a little from the spec, so that we create a
complete Block in one go instead of creating an empty one and then
poking at its internals.

Userland/Libraries/LibWeb/CSS/Parser/Block.cpp

@@ -9,12 +9,12 @@
 
 namespace Web::CSS::Parser {
 
-Block::Block() = default;
 Block::Block(Token token, Vector<ComponentValue>&& values)
     : m_token(move(token))
     , m_values(move(values))
 {
 }
+
 Block::~Block() = default;
 
 String Block::to_string() const