this review is extracted from D86539.
1. Rename AccelTableKind to DwarfLinkerAccelTableKind
(to differentiate from AccelTableKind from CodeGen/AsmPrinter/DwarfDebug.h)
2. Add None value to the DwarfLinkerAccelTableKind.
3. added 'None' value for 'accelerator' option of dsymutil.
Differential Revision: https://reviews.llvm.org/D125474