cmd/link/internal/arm: fix off-by-1 in trampoline reachability computation
Tweak the code in trampoline generation that determines if a given
call branch will reach, changing the lower limit guard from "x <
-0x800000" to "x <= -0x800000". This is to resolve linking failures
when the computed displacement is exactly -0x800000, which results in
errors of the form
.../ld.gold: internal error in arm_branch_common, at ../../gold/arm.cc:4079
when using the Gold linker, and
...:(.text+0x...): relocation truncated to fit: R_ARM_CALL against `runtime.morestack_noctxt'
when using the bfd linker.
Fixes #59034.
Updates #58425.
Change-Id: I8a76986b38727df1b961654824c2af23f06b9fcf
Reviewed-on: https://go-review.googlesource.com/c/go/+/475957
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>