Instead of writing out the type almost twice in the symbol name,
teach the linker how to sort typelink symbols by their contents.
This ~halves the size of typelink symbol names, which helps very
large (6KB) names like those mentioned in #15104.
This does not increase the total sorting work done by the linker,
and makes it possible to use shorter symbol names for types. See
the follow-on CL 21583.
Change-Id: Ie5807565ed07d31bc477d20f60e4c0b47144f337
Reviewed-on: https://go-review.googlesource.com/21457 Reviewed-by: Ian Lance Taylor <iant@golang.org>