Rollup merge of #121031 - TimNN:lh-fix-20240213, r=durin42

RustWrapper: adapt for coverage mapping API changes

There've been a number of changes to the coverage mapping API today, but the end result is that specifying the MCDC parameters is now optional (they've been moved to the end of the argument list and now default to `std::monostate`).

`@rustbot` label: +llvm-main

r? `@durin42`

compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp

@@ -139,7 +139,7 @@ extern "C" void LLVMRustCoverageWriteMappingToBuffer(
            RustMappingRegions, NumMappingRegions)) {
     MappingRegions.emplace_back(
         fromRust(Region.Count), fromRust(Region.FalseCount),
-#if LLVM_VERSION_GE(18, 0)
+#if LLVM_VERSION_GE(18, 0) && LLVM_VERSION_LT(19, 0)
         coverage::CounterMappingRegion::MCDCParameters{},
 #endif
         Region.FileID, Region.ExpandedFileID,