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.
This commit changes how inline information is stored in SILDebugScope
from a tree to a linear chain of inlined call sites (similar to what
LLVM is using). This makes creating inlined SILDebugScopes slightly
more expensive, but makes lowering SILDebugScopes into LLVM metadata
much faster because entire inlined-at chains can now be cached. This
means that SIL is no longer preserve the inlining history (i.e., ((a
was inlined into b) was inlined into c) is represented the same as (a
was inlined into (b was inlined into c)), but this information was not
used by anyone.
On my late 2012 i7 iMac, this saves about 4 seconds when compiling the
RelWithDebInfo x86_64 swift standard library — or 40% of IRGen time.
rdar://problem/28311051
