Multiple capabilities not mapped to extensions in SPIRVCapability::getRequiredExtension()

Currently, the `SPIRVCapability::getRequiredExtension()` switch only covers a few cases, whereas multiple extension implementations have missed this mapping. TBD:
1. Review the extension/capability list and add the missing tokens into the function body
2. Change the function's switch statement to `switch (static_cast(Kind))` so as to silence warnings for `internal::` capabilities (practically done in https://github.com/KhronosGroup/SPIRV-LLVM-Translator/pull/1053).