Missing features:
* keys other than strings
* more than 8 values in the hashmap
* growing a map when needed
* initial size hint
* delete(m, key)
* iterators (for range)
* initializing global maps
* ...more?
This is a big combined change. Other changes in this commit:
* Analyze makeinterface and make sure type switches don't include
unnecessary cases.
* Do not include CGo wrapper functions in the analyzer callgraph.
This also avoids some unnecessary type IDs.
* Give all Go named structs a name in LLVM.
* Use such a named struct for compiler-generated task data.
* Use the type and function names defined by the ssa and types
package instead of generating our own.
* Some improvements to function pointers.
* A few other minor improvements.
The one thing lacking here is interface-to-interface assertions.
