Add missing %target-codesigns to a couple of tests

Author: hamishknight

test/SILOptimizer/target-const-prop.swift

@@ -3,6 +3,7 @@
 // Make a runtime test to check that the values are correct.
 // RUN: %empty-directory(%t) 
 // RUN: %target-build-swift -O -module-name=test %s -o %t/a.out
+// RUN: %target-codesign %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s -check-prefix=CHECK-OUTPUT
 
 // REQUIRES: executable_test,optimized_stdlib