Type annotations for instruction operands are omitted, e.g.
```
%3 = struct $S(%1, %2)
```
Operand types are redundant anyway and were only used for sanity checking in the SIL parser.
But: operand types _are_ printed if the definition of the operand value was not printed yet.
This happens:
* if the block with the definition appears after the block where the operand's instruction is located
* if a block or instruction is printed in isolation, e.g. in a debugger
The old behavior can be restored with `-Xllvm -sil-print-types`.
This option is added to many existing test files which check for operand types in their check-lines.
Commit 53754a7a69 added a module pass that serializes the entire module.
Part of that pass is a method called removeSerializedFlagFromAllFunctions that removes the serialized flag from all functions within the module, which allows for more optimizations and for a better dead function elimination.
The problem is that this might break the Devirtualizer: If we run Devirtualization after “SerializeSILPass”, and we do LinkAll after Devirtualizing a function, SIL Verifier will fail: a public_external [serialized] function might be calling a [serialized] function for which we removed the [serialized] flag and added said flag to the module itself.
The verifier thinks that a function_ref inside fragile function is referencing private or hidden symbol.
