[llvm] [Offload] Implement `olShutDown` (PR #144055)

[Ross Brunton via llvm-commits]

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@@ -130,6 +131,9 @@ constexpr ol_platform_backend_t pluginNameToBackend(StringRef Name) {
 #include "Shared/Targets.def"
 
 void initPlugins() {
+  PlatformList = new PlatformVecT();
+  AllocInfoMap = new AllocInfoMapT();
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RossBrunton wrote:

`unique_ptr` doesn't work here because of the destruction order of statics. `olShutDown` requires the platforms list to be valid (so it can loop through them and deinit them). However if you call `olShutDown` in the destructor of a static (e.g. https://github.com/llvm/llvm-project/blob/main/offload/unittests/OffloadAPI/common/Environment.cpp#L20 ), then the `unique_ptr` might get freed before `olShutDown` is ran.

https://github.com/llvm/llvm-project/pull/144055