[llvm] [PluginLoader] Drop legacy -load option from llc (PR #217860)

[Stefan Gränitz via llvm-commits]

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@@ -49,7 +49,6 @@
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/PGOOptions.h"
 #include "llvm/Support/Path.h"
-#include "llvm/Support/PluginLoader.h"
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weliveindetail wrote:

It was supposed to go away in https://github.com/llvm/llvm-project/pull/117644, but then reverted in https://github.com/llvm/llvm-project/pull/182455 due to the test in this patch. Actually, I should include the docs change.

> If we remove this here, why do we keep it in opt, llvm-lto2, lld, and clang-tidy?

I haven't checked the details for the others. Let's go one step at a time.

https://github.com/llvm/llvm-project/pull/217860