message: Move swift-lldb changes from ExpressionSourceCode.cpp to
  SwiftExpressionSourceCode.cpp (NFC)
diff: @@ -20,16 +20,12 @@ using namespace lldb;
  using namespace lldb_private;
  /// Format the OS name the way that Swift availability attributes do.
  -static llvm::StringRef getAvailabilityName(llvm::Triple::OSType os) {
  - switch (os) {
  - case llvm::Triple::MacOSX: return "macOS";
  - case llvm::Triple::IOS: return "iOS";
  - case llvm::Triple::TvOS: return "tvOS";
  - case llvm::Triple::WatchOS: return "watchOS";
  - default:
  - return llvm::Triple::getOSTypeName(os);
  - }
  +static llvm::StringRef getAvailabilityName(const llvm::Triple &triple) {
  + swift::LangOptions lang_options;
  + lang_options.setTarget(triple);
  + return swift::platformString(swift::targetPlatform(lang_options));
  }
  +
  uint32_t SwiftExpressionSourceCode::GetNumBodyLines() {
  if (m_num_body_lines == 0)
  // 2 = <one for zero indexing> + <one for the body start marker>
  @@ -83,7 +79,7 @@ bool SwiftExpressionSourceCode::GetText(
  auto triple = arch_spec.GetTriple();
  if (triple.isOSDarwin()) {
  if (auto process_sp = exe_ctx.GetProcessSP()) {
  - os_vers << getAvailabilityName(triple.getOS()) << " ";
  + os_vers << getAvailabilityName(triple) << " ";
  auto platform = target->GetPlatform();
  bool is_simulator =
  platform->GetPluginName().GetStringRef().endswith("-simulator");
  @@ -97,6 +93,7 @@ bool SwiftExpressionSourceCode::GetText(
  }
  }
  }
  +
  SwiftPersistentExpressionState *persistent_state =
  llvm::cast<SwiftPersistentExpressionState>(target->GetPersistentExpressionStateForLanguage(lldb::eLanguageTypeSwift));
  std::vector<swift::ValueDecl *> persistent_results;
  