The current Zephyr-sdk v0.18.0-alpha2 breaks bisectability.

The v0.18.0-alpha2 LLVM requires work in https://github.com/zephyrproject-rtos/zephyr/commits/collab-sdk-0.18-dev/, which in general is acceptable, however during a git bisect on zephyr/main, then work in this branch (even when merged to zephyr/main in future) will not be available, and therefore it will not be possible to do a git bisect which includes revisions before the work found in collab-sdk-0.18-dev.

Also it should be possible for users to work with older Zephyr releases, like v3.7.0 and v4.0.0 and still have Zephyr sdk v0.18.0 installed.

Before releasing Zephyr sdk v0.18.0 it should be ensured that older Zephyr revisions can still build, even if this v0.18.0 is also installed.
Especially to guarantee that a git bisect will still work.

Error seen when Zephyr sdk v0.18.0-alpha2 is installed without changes from collab-sdk-0.18-dev.

-- ZEPHYR_TOOLCHAIN_VARIANT not set, trying to locate Zephyr SDK
-- Found host-tools: zephyr 0.18.0 (/opt/zephyr-sdk-0.18.0-alpha2)
CMake Error at /projects/github/ncs/zephyr/cmake/modules/FindHostTools.cmake:104 (include):
  include could not find requested file:

    /projects/github/ncs/zephyr/cmake/toolchain/zephyr-gnu/generic.cmake
Call Stack (most recent call first):
  /projects/github/ncs/zephyr/cmake/modules/dts.cmake:9 (find_package)
  /projects/github/ncs/zephyr/cmake/modules/zephyr_default.cmake:133 (include)
  /projects/github/ncs/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
  /projects/github/ncs/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:117 (include_boilerplate)
  CMakeLists.txt:5 (find_package)