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.
Constant-propagate the 0 value when loading "count" or "capacity" from the empty Array, Set or Dictionary storage.
On high-level SIL this optimization is also done by the ArrayCountPropagation pass, but only for Array.
And even for Array it's sometimes needed to propagate the empty-array count when high-level semantics function are already inlined.
Fixes an optimization deficiency for empty OptionSet literals.
https://bugs.swift.org/browse/SR-12046
rdar://problem/58861171
