[llvm] [mlir] [OpenMP][MLIR] Hoist static `alloca`s emitted by private `init` regions to the allocation IP of the construct (PR #171597)

[Tom Eccles via llvm-commits]

================
@@ -2348,6 +2348,7 @@ class OpenMPIRBuilder {
     PostOutlineCBTy PostOutlineCB;
     BasicBlock *EntryBB, *ExitBB, *OuterAllocaBB;
     SmallVector<Value *, 2> ExcludeArgsFromAggregate;
+    bool FixUpNonEntryAllocas = false;
----------------
tblah wrote:

```suggestion
    // TODO: this should be safe to enable by default
    bool FixUpNonEntryAllocas = false;
```

https://github.com/llvm/llvm-project/pull/171597