Ensure that we account for indirect error results in SILFunction/SILInstruction

These were only properly handling SIL-level indirect results, not
including indirect error results.

Author: DougGregor

include/swift/SIL/SILFunction.h

@@ -1455,7 +1455,8 @@ class SILFunction
   ArrayRef<SILArgument *> getArgumentsWithoutIndirectResults() const {
     assert(!empty() && "Cannot get arguments of a function without a body");
     return begin()->getArguments().slice(
-        getConventions().getNumIndirectSILResults());
+        getConventions().getNumIndirectSILResults() +
+          getConventions().getNumIndirectSILErrorResults());
   }
 
   const SILArgument *getSelfArgument() const {

include/swift/SIL/SILInstruction.h

@@ -2902,7 +2902,9 @@ class ApplyInstBase<Impl, Base, true>
     return getSubstCalleeConv().hasIndirectSILResults();
   }
   unsigned getNumIndirectResults() const {
-    return getSubstCalleeConv().getNumIndirectSILResults();
+    auto fnConv = getSubstCalleeConv();
+    return fnConv.getNumIndirectSILResults() +
+        fnConv.getNumIndirectSILErrorResults();
   }
 
   bool hasSelfArgument() const {