[clang] [analyzer] Import CTU constant initializers on demand (PR #231393)

[via cfe-commits]

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@@ -539,11 +539,8 @@ class RegionStoreManager : public StoreManager {
   Loc getLValueVar(const VarDecl *VD, const StackFrame *SF) override {
     // Import before creating the region: the definition can complete an array
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relaxcn wrote:

Agree. I replaced it with:

```cpp
    // Consider importing from another translation unit before creating the region:
    // the definition can complete an array type and becomes the declaration used
    // to identify the region.
```

https://github.com/llvm/llvm-project/pull/231393