[TCWG-614] Range extension thunks
- LLD now uses synthetic sections for Thunks.
ARM Thunks now have symbols and mapping symbols.
As a side-effect we can now create local symbols in synthetic sections
so I've added them to the ARM PLT sections.
[Misc]
- Wrote 3 lines of lld 4.0 release notes for AR
== Progress ==
* National holiday on Tuesday [2/10]
* [AArch64] Investigate PR30225 [TCWG-1021] [2/10]
- This was a bug related to the code alignment factor for the debug frame
- Decided it was not a correctness issue and the size savings for
using a different factor are probably not noticeab
