* Extract Call ast node tag out of SuffixOp; parameters go in memory
after Call.
* Demote AsmInput and AsmOutput from AST nodes to structs inside the
Asm node.
* The following ast nodes get their sub-node lists directly following
them in memory:
- ErrorSetDecl
- Switch
- BuiltinCall
* ast.Node.Asm gets slices for inputs, outputs, clobbers instead of
singly linked lists
Performance changes:
throughput: 72.7 MiB/s => 74.0 MiB/s
maxrss: 72 KB => 69 KB (nice)