Merge pull request swiftlang#23319 from compnerd/coff-metadata-section

IRGen: correct field metadata section name on COFF

Author: compnerd

lib/IRGen/GenDecl.cpp

@@ -2858,7 +2858,7 @@ llvm::Constant *IRGenModule::emitFieldDescriptors() {
     sectionName = "swift5_fieldmd";
     break;
   case llvm::Triple::COFF:
-    sectionName = ".swift5_fieldmd";
+    sectionName = ".sw5flmd$B";
     break;
   case llvm::Triple::UnknownObjectFormat:
     llvm_unreachable("Don't know how to emit field records table for "