[JITLink] Remove the Section::symbols_empty() method.

llvm::empty(Sec.symbols()) can be used instead.
diff --git a/llvm/tools/llvm-jitlink/llvm-jitlink.cpp b/llvm/tools/llvm-jitlink/llvm-jitlink.cpp
index f5b8418..de52bb9 100644
--- a/llvm/tools/llvm-jitlink/llvm-jitlink.cpp
+++ b/llvm/tools/llvm-jitlink/llvm-jitlink.cpp
@@ -174,11 +174,11 @@
 
   std::sort(Sections.begin(), Sections.end(),
             [](const Section *LHS, const Section *RHS) {
-              if (LHS->symbols_empty() && RHS->symbols_empty())
+              if (llvm::empty(LHS->symbols()) && llvm::empty(RHS->symbols()))
                 return false;
-              if (LHS->symbols_empty())
+              if (llvm::empty(LHS->symbols()))
                 return false;
-              if (RHS->symbols_empty())
+              if (llvm::empty(RHS->symbols()))
                 return true;
               SectionRange LHSRange(*LHS);
               SectionRange RHSRange(*RHS);
@@ -187,7 +187,7 @@
 
   for (auto *S : Sections) {
     OS << S->getName() << " content:";
-    if (S->symbols_empty()) {
+    if (llvm::empty(S->symbols())) {
       OS << "\n  section empty\n";
       continue;
     }