cmd/compile: for arm64 epilog, do SP increment with a single instruction
That way, the frame is atomically popped. Previously, for big frames
the SP was unwound in two steps (because arm64 can only add constants
up to 1<<12 in a single instruction).
Fixes #73259
Change-Id: I382c249194ad7bc9fc19607c27487c58d90d49e5
Reviewed-on: https://go-review.googlesource.com/c/go/+/689235
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Keith Randall <khr@google.com>