runtime: don't call lockOSThread for every syscall call on Windows

Windows syscall.SyscallN currently calls lockOSThread for every syscall.
This can be expensive and produce unnecessary context switches,
especially when the syscall is called frequently under high contention.

The lockOSThread was necessary to ensure that cgocall wouldn't
reschedule the goroutine to a different M, as the syscall return values
are reported back in the M struct.

This CL instructs cgocall to copy the syscall return values into the
the M that will see the caller on return, so the caller no longer needs
to call lockOSThread.

Updates #58336.

Cq-Include-Trybots: luci.golang.try:gotip-windows-arm64,gotip-windows-amd64-longtest
Change-Id: If6644fd111dbacab74e7dcee2afa18ca146735da
Reviewed-on: https://go-review.googlesource.com/c/go/+/562915
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Auto-Submit: Emmanuel Odeke <emmanuel@orijtech.com>
Reviewed-by: Than McIntosh <thanm@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

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