[DWARF] Remove collectChildrenAddressRanges (NFC)

The last use was removed on Dec 21, 2018 in commit
c3f30a7.

llvm/include/llvm/DebugInfo/DWARF/DWARFDie.h

@@ -220,16 +220,6 @@ class DWARFDie {
   /// information is available.
   Expected<DWARFAddressRangesVector> getAddressRanges() const;
 
-  /// Get all address ranges for any DW_TAG_subprogram DIEs in this DIE or any
-  /// of its children.
-  ///
-  /// Get the hi/low PC range if both attributes are available or exrtracts the
-  /// non-contiguous address ranges from the DW_AT_ranges attribute for this DIE
-  /// and all children.
-  ///
-  /// \param Ranges the addres range vector to fill in.
-  void collectChildrenAddressRanges(DWARFAddressRangesVector &Ranges) const;
-
   bool addressRangeContainsAddress(const uint64_t Address) const;
 
   Expected<DWARFLocationExpressionsVector>

llvm/lib/DebugInfo/DWARF/DWARFDie.cpp

@@ -483,21 +483,6 @@ Expected<DWARFAddressRangesVector> DWARFDie::getAddressRanges() const {
   return DWARFAddressRangesVector();
 }
 
-void DWARFDie::collectChildrenAddressRanges(
-    DWARFAddressRangesVector &Ranges) const {
-  if (isNULL())
-    return;
-  if (isSubprogramDIE()) {
-    if (auto DIERangesOrError = getAddressRanges())
-      llvm::append_range(Ranges, DIERangesOrError.get());
-    else
-      llvm::consumeError(DIERangesOrError.takeError());
-  }
-
-  for (auto Child : children())
-    Child.collectChildrenAddressRanges(Ranges);
-}
-
 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
   auto RangesOrError = getAddressRanges();
   if (!RangesOrError) {