[LTO] Perform DSOLocal propagation in combined index

Perform DSOLocal propagation within summary list of every GV. This
avoids the repeated query of this information during function
importing.

Differential Revision: https://reviews.llvm.org/D96398

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -6845,7 +6845,7 @@ static Expected<bool> getEnableSplitLTOUnitFlag(BitstreamCursor &Stream,
     case bitc::FS_FLAGS: { // [flags]
       uint64_t Flags = Record[0];
       // Scan flags.
-      assert(Flags <= 0x3f && "Unexpected bits in flag");
+      assert(Flags <= 0x7f && "Unexpected bits in flag");
 
       return Flags & 0x8;
     }