tools/testbuild.sh: add option -N use CMake with Ninja

[simbit18]

Summary

tools/testbuild.sh
added option -N Use CMake with Ninja as the backend.
updated help.
added date to print startup board

====================================================================================
Cmake in present: nucleo-l152re/nsh,CONFIG_ARM_TOOLCHAIN_GNU_EABI
Configuration/Tool: nucleo-l152re/nsh,CONFIG_ARM_TOOLCHAIN_GNU_EABI
2024-07-16 14:39:57
------------------------------------------------------------------------------------

added HOST=Msys

github/workflows/build.yml

added option -N job docker

Impact

There should be no impact.

Testing

ci

[simbit18]

https://github.com/apache/nuttx/actions/runs/9970183739/job/27548653008?pr=12721#step:7:572
CMake Error at /github/workspace/sources/nuttx/build/_deps/dtc-subbuild/dtc-populate-prefix/src/dtc-populate-stamp/download-dtc-populate.cmake:170 (message):
Each download failed!

error: downloading 'https://github.com/dgibson/dtc/archive/v1.7.0.zip' failed
      status_code: 28
      status_string: "Timeout was reached"
      log:
      --- LOG BEGIN ---
        Trying 140.82.112.3:443...

connect to 140.82.112.3 port 443 failed: Connection timed out

Failed to connect to github.com port 443 after 134346 ms: Couldn't connect
to server

It does not depend on this PR.
I will rebase to see if this can fix the CI error.