[dev.link] cmd/link: add support for "not in symbol table" attribute
Add loader.Loader support for recording whether symbols should appear
in the symbol table (e.g. AttrNotInSymbolTable). Change the preloader
to apply this attribute to selected symbols (e.g. go.string.*,
runtime.gcbits.*) during the initial scan over object file defs, since
at that point the name is available.
Change-Id: I54be9a649107e90c0fd544a1c0ba87e2d98833ad
Reviewed-on: https://go-review.googlesource.com/c/go/+/213778
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Jeremy Faller <jeremy@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>