[ObjectOutliner] See through move_value insts.

Enables the outlining of the ContiguousArrayStorage<StaticString> used
when initializing a RawRepresentable enum whose RawValue is String into
a global value to continue even when ContiguousArrayStorage has a
lexical lifetime.

Addresses the following regressions

StringEnumRawValueInitialization    400     7680    +1820.0%   **0.05x**
ArrayLiteral2                       78      647     +729.5%    **0.12x**
DataCreateSmallArray                1750    8850    +405.7%    **0.20x**

seen when enabling lexical lifetimes in the standard library.

Author: nate-chandler

lib/SILOptimizer/Transforms/ObjectOutliner.cpp

@@ -252,6 +252,11 @@ bool ObjectOutliner::getObjectInitVals(SILValue Val,
       if (!getObjectInitVals(UC, MemberStores, TailStores, NumTailTupleElements,
                              toIgnore))
         return false;
+    } else if (auto *mvi = dyn_cast<MoveValueInst>(User)) {
+      // move_value is transparent.
+      if (!getObjectInitVals(mvi, MemberStores, TailStores, NumTailTupleElements,
+                             toIgnore))
+        return false;
     } else if (auto *REA = dyn_cast<RefElementAddrInst>(User)) {
       // The address of a stored property.
       for (Operand *ElemAddrUse : REA->getUses()) {
@@ -316,6 +321,9 @@ static EndCOWMutationInst *getEndCOWMutation(SILValue object) {
       // Look through upcast instructions.
       if (EndCOWMutationInst *ecm = getEndCOWMutation(upCast))
         return ecm;
+    } else if (auto *mvi = dyn_cast<MoveValueInst>(user)) {
+      if (auto *ecm = getEndCOWMutation(mvi))
+        return ecm;
     } else if (auto *ecm = dyn_cast<EndCOWMutationInst>(use->getUser())) {
       return ecm;
     }