swift234

Add 1 more iteration of release hoisting.

I see that we go from 24.9% of time spent in SILOptimizations in stdlib compilation
to 25.2%.

This brings back 50% of the regression for StringWithCString.

  <summary>Regression (3)</summary>

TEST                                                    | OLD_MIN | NEW_MIN | DELTA (%) | SPEEDUP
---                                                     | ---     | ---     | ---       | ---
NSError                                                 | 255     | 296     | +16.1%    | **0.86x**
ObjectiveCBridgeStubToArrayOfNSString                   | 25087   | 27733   | +10.6%    | **0.90x**
SwiftStructuresInsertionSort                            | 4292    | 4557    | +6.2%     | **0.94x**

</details>

<details >
  <summary>Improvement (7)</summary>

TEST                                                    | OLD_MIN | NEW_MIN | DELTA (%) | SPEEDUP
---                                                     | ---     | ---     | ---       | ---
MatMul                                                  | 1135    | 1071    | -5.6%     | **1.06x**
ObjectiveCBridgeToNSArray                               | 27090   | 25566   | -5.6%     | **1.06x**
ObjectiveCBridgeFromNSArrayAnyObjectToString            | 155362  | 145067  | -6.6%     | **1.07x**
OpenClose                                               | 47      | 44      | -6.4%     | **1.07x**
StringHasSuffix                                         | 695     | 642     | -7.6%     | **1.08x**
Calculator                                              | 34      | 30      | -11.8%    | **1.13x**
StringWithCString                                       | 336135  | 164974  | -50.9%    | **2.04x**