LibRegex: Avoid excessive Vector copy when compiling regexps

Previously we would've copied the bytecode instead of moving the chunks
around, use the fancy new DisjointChunks<T> abstraction to make that
happen automagically.
This decreases vector copies and uses of memmove() by nearly 10x :^)

Userland/Libraries/LibRegex/RegexBytecodeStreamOptimizer.h

@@ -12,7 +12,7 @@ namespace regex {
 
 class Optimizer {
 public:
-    static void append_alternation(ByteCode& target, ByteCode& left, ByteCode& right);
+    static void append_alternation(ByteCode& target, ByteCode&& left, ByteCode&& right);
 };
 
 }