llvm: disable remarks support on LLVM 22

LLVM change dfbd76bda01e removed separate remark support entirely.
That's the only mode we actually used, and it doesn't appear to be a
quick change to clean that up. It also appears to be a relatively
obscure unstable feature from looking in the test suite, so I'll disable
it in LLVM 22 for now so we continue to get CI coverage for the rest of
our functionality.

Fixes #146912 as far as I can tell (the test passes.)

@rustbot label llvm-main

Author: durin42

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -1779,9 +1779,14 @@ extern "C" void LLVMRustContextConfigureDiagnosticHandler(
     // Do not delete the file after we gather remarks
     RemarkFile->keep();
 
+#if LLVM_VERSION_GE(22, 0)
+    auto RemarkSerializer = remarks::createRemarkSerializer(
+        llvm::remarks::Format::YAML, RemarkFile->os());
+#else
     auto RemarkSerializer = remarks::createRemarkSerializer(
         llvm::remarks::Format::YAML, remarks::SerializerMode::Separate,
         RemarkFile->os());
+#endif
     if (Error E = RemarkSerializer.takeError()) {
       std::string Error = std::string("Cannot create remark serializer: ") +
                           toString(std::move(E));