constant_evaluable_subset - update test to enable optimization

Constant evaluation actually requires optimization to kick in. At
least in some of the tests. For example, alloc_box must be promoted.

Author: atrick

test/SILOptimizer/constant_evaluable_subset_test.swift

@@ -4,7 +4,7 @@
 // Run the (mandatory) passes on which constant evaluator depends, and test the
 // constant evaluator on the SIL produced after the dependent passes are run.
 //
-// RUN: not %target-sil-opt -silgen-cleanup -raw-sil-inst-lowering -allocbox-to-stack -mandatory-inlining -constexpr-limit 3000 -test-constant-evaluable-subset %t/constant_evaluable_subset_test_silgen.sil > %t/constant_evaluable_subset_test.sil 2> %t/error-output
+// RUN: not %target-sil-opt -opt-mode=speed -silgen-cleanup -raw-sil-inst-lowering -allocbox-to-stack -mandatory-inlining -constexpr-limit 3000 -test-constant-evaluable-subset %t/constant_evaluable_subset_test_silgen.sil > %t/constant_evaluable_subset_test.sil 2> %t/error-output
 //
 // RUN: %FileCheck %S/Inputs/constant_evaluable.swift < %t/error-output
 //
@@ -14,6 +14,6 @@
 // especially performance inlining as it inlines functions such as String.+=
 // that the evaluator has special knowledge about.
 //
-// RUN: not %target-sil-opt -silgen-cleanup -diagnose-invalid-escaping-captures -diagnose-static-exclusivity -capture-promotion -access-enforcement-selection -allocbox-to-stack -noreturn-folding -definite-init -raw-sil-inst-lowering -closure-lifetime-fixup -semantic-arc-opts -destroy-hoisting -ownership-model-eliminator -mandatory-inlining -predictable-memaccess-opts -os-log-optimization -diagnostic-constant-propagation -predictable-deadalloc-elim -mandatory-arc-opts -diagnose-unreachable -diagnose-infinite-recursion -yield-once-check -dataflow-diagnostics -split-non-cond_br-critical-edges -constexpr-limit 3000 -test-constant-evaluable-subset %t/constant_evaluable_subset_test_silgen.sil > /dev/null 2> %t/error-output-mandatory
+// RUN: not %target-sil-opt -opt-mode=speed -silgen-cleanup -diagnose-invalid-escaping-captures -diagnose-static-exclusivity -capture-promotion -access-enforcement-selection -allocbox-to-stack -noreturn-folding -definite-init -raw-sil-inst-lowering -closure-lifetime-fixup -semantic-arc-opts -destroy-hoisting -ownership-model-eliminator -mandatory-inlining -predictable-memaccess-opts -os-log-optimization -diagnostic-constant-propagation -predictable-deadalloc-elim -mandatory-arc-opts -diagnose-unreachable -diagnose-infinite-recursion -yield-once-check -dataflow-diagnostics -split-non-cond_br-critical-edges -constexpr-limit 3000 -test-constant-evaluable-subset %t/constant_evaluable_subset_test_silgen.sil > /dev/null 2> %t/error-output-mandatory
 //
 // RUN: %FileCheck %S/Inputs/constant_evaluable.swift < %t/error-output-mandatory