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.

@rustbot label llvm-main

Author: durin42

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -1762,6 +1762,9 @@ extern "C" void LLVMRustContextConfigureDiagnosticHandler(
   std::unique_ptr<LLVMRemarkStreamer> LlvmRemarkStreamer;
 
   if (RemarkFilePath != nullptr) {
+#if LLVM_VERSION_GE(22, 0)
+    report_fatal_error("optimization remark-dir unimplemented on LLVM 22 and later");
+#else
     if (PGOAvailable) {
       // Enable PGO hotness data for remarks, if available
       unwrap(C)->setDiagnosticsHotnessRequested(true);
@@ -1790,6 +1793,7 @@ extern "C" void LLVMRustContextConfigureDiagnosticHandler(
     RemarkStreamer = std::make_unique<llvm::remarks::RemarkStreamer>(
         std::move(*RemarkSerializer));
     LlvmRemarkStreamer = std::make_unique<LLVMRemarkStreamer>(*RemarkStreamer);
+#endif
   }
 
   unwrap(C)->setDiagnosticHandler(std::make_unique<RustDiagnosticHandler>(