[BOLT] Remove redundant const from return types (NFC)

Identified with readability-const-return-type.

Author: kazutakahirata

bolt/include/bolt/Core/BinaryFunction.h

@@ -1005,7 +1005,7 @@ class BinaryFunction {
   Optional<StringRef> hasRestoredNameRegex(const StringRef NameRegex) const;
 
   /// Return a vector of all possible names for the function.
-  const std::vector<StringRef> getNames() const {
+  std::vector<StringRef> getNames() const {
     std::vector<StringRef> AllNames;
     forEachName([&AllNames](StringRef Name) {
       AllNames.push_back(Name);
@@ -1427,17 +1427,15 @@ class BinaryFunction {
 
   const CallSitesType &getColdCallSites() const { return ColdCallSites; }
 
-  const ArrayRef<uint8_t> getLSDAActionTable() const { return LSDAActionTable; }
+  ArrayRef<uint8_t> getLSDAActionTable() const { return LSDAActionTable; }
 
   const LSDATypeTableTy &getLSDATypeTable() const { return LSDATypeTable; }
 
   const LSDATypeTableTy &getLSDATypeAddressTable() const {
     return LSDATypeAddressTable;
   }
 
-  const ArrayRef<uint8_t> getLSDATypeIndexTable() const {
-    return LSDATypeIndexTable;
-  }
+  ArrayRef<uint8_t> getLSDATypeIndexTable() const { return LSDATypeIndexTable; }
 
   const LabelsMapType &getLabels() const { return Labels; }