* add TypedValue.Managed which represents a Type, a Value, and some
kind of memory management strategy.
* introduce an analysis queue
* flesh out how incremental compilation works with respect to exports
* ir.text.Module is only capable of one error message during parsing
* link.zig no longer has a decl table map and instead has structs that
exist directly on ir.Module.Decl and ir.Module.Export
* implement primitive .text block allocation
* implement linker code for updating Decls and Exports
* implement null Type
Some supporting std lib changes:
* add std.ArrayList.appendSliceAssumeCapacity
* add std.fs.File.copyRange and copyRangeAll
* fix std.HashMap having modification safety on in ReleaseSmall builds
* add std.HashMap.putAssumeCapacityNoClobber
Andrew Kelley