QXmlStreamGrammar::spell causes unnecessary relocations

The problem is that the object is of type array-of-pointers, well-known for causing relocations. While the solution would usually be trivial (use qOffsetStringArray), there are three complications here:

• the variable is generated by qlalr, so the generator first needs to be fixed
• the table contains nullptr entries (encoded as 0), which, when significant, cannot be handled by qOffsetStringArray
• the header is included in two different TUs while qOffsetStringArray realy likes being a constexpr auto static.