[clang] [Frontend] Move -mllvm and loading of plugins to address a fixme. NFC (PR #192476)

[Vassil Vassilev via cfe-commits]

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@@ -418,6 +418,8 @@ void dependencies::initializeScanCompilerInstance(
     DiagnosticConsumer *DiagConsumer, DependencyScanningService &Service,
     IntrusiveRefCntPtr<DependencyScanningWorkerFilesystem> DepFS) {
   ScanInstance.setBuildingModule(false);
+  // LLVM options are not going to affect dependency scanning.
+  ScanInstance.getFrontendOpts().LLVMArgs.clear();
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vgvassilev wrote:

I am also a bit confused -- somehow we have llvm options already passed but we do not initialize any targets. Let me put another version of my patch without changing the clients code...

https://github.com/llvm/llvm-project/pull/192476