[+0-all-args] When emitting for each statements, make sure to call unreachableExit from the Switch Case Scope.

This will allow me to enforce with an assert that the switch case scope is
always exitted in an explicit way.

Author: gottesmm

lib/SILGen/SILGenStmt.cpp

@@ -867,8 +867,10 @@ void StmtEmitter::visitForEachStmt(ForEachStmt *S) {
 
         // If we emitted an unreachable in the body, we will not have a valid
         // insertion point. Just return early.
-        if (!SGF.B.hasValidInsertionPoint())
+        if (!SGF.B.hasValidInsertionPoint()) {
+          scope.unreachableExit();
           return;
+        }
 
         // Otherwise, associate the loop body's closing brace with this branch.
         RegularLocation L(S->getBody());