cmd/compile: fix transitive inlining of generic functions
If an imported, non-generic function F transitively calls a generic
function G[T], we may need to call CanInline on G[T].
While here, we can also take advantage of the fact that we know G[T]
was already seen and compiled in an imported package, so we don't need
to call InlineCalls or add it to typecheck.Target.Decls. This saves us
from wasting compile time re-creating DUPOK symbols that we know
already exist in the imported package's link objects.
Fixes #56280.
Change-Id: I3336786bee01616ee9f2b18908738e4ca41c8102
Reviewed-on: https://go-review.googlesource.com/c/go/+/443535
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>