Add mtest 1.2.0 build 0

[mikeleppane]

Updates mtest from 1.1.0 to 1.2.0.

• Source: mikeleppane/mtest@0668b52 (tag v1.2.0)
• Toolchain: mojo ==1.1.0 / mojo-compiler ==1.1.0 (was 1.0.0b2)
• Platforms: linux-64 and osx-arm64; linux-aarch64 stays skipped
• The recipe is unchanged apart from the version, source rev and Mojo pins. It was built and tested on linux-64 and osx-arm64 before submission.

Release notes: https://github.com/mikeleppane/mtest/releases/tag/v1.2.0

Checklist

• My recipe.yaml file specifies which version(s) of MAX is compatible with my project (see here for an example). If not, my package is compatible with both 24.5 and 24.6.
• License file is packaged (see here for an example).
• Set the build number to 0 (for new packages, or if the version changed).
• Bumped the build number (if the version is unchanged).

[alisterburt]

thank you @mikeleppane !