run: move general AMT support to tool/run

Issue #679
run: add Intel AMT support to x86 kernels

Issue #679
run: add Pulsar PXE boot support for x86 kernels

Issue #679
run: PXE+AMT support for x86 kernels

Issue #679
lwip: adjust test to run with remote machine (AMT)

Issue #679
run scripts: add "Test succeeded" message

Issue #679
libports: make include paths absolute

If contrib and/or download in libports are symlinks, then using ".." ends up
in the wrong directory.
noux: add script to run start/stop automatically

Issue #679
run: add support to query qemu support

To be used by the base-* specific run/env scripts to choose the appropriate
test backend.
run: introduce explicit wait_for_output

To be used by base-* run/env scripts
net: add library for performance measurements
net: net_stat instrumented version of iPXE driver
net: net_stat instrumented version of usb_drv
extend genode_until_run for nova, foc, hw
test: nic session client using net_stat lib

A simple nic session client using the performance measurement library.
run: lwip use is_qemu
run: support RUN_OPT for all platforms

Use RUN_OPT="--target ..." to select the backend test method.

Supported values so far:

qemu     - qemu + grub bootloader (default)
qemu+pxe - qemu + pulsar bootloader (PXE)
amt      - Intel AMT (reset+serial output) + pulsar bootloader

Related to issue #598
dde_ipxe: fix null pointer de-referencing
dde_ipxe: catch exception instead of dying silently
check wakeup situation in rx() after dequeuing

Issue #593