COMMON_TEST_* executables aren't installed when building with -DBUILD_TESTING=OFF

[scpeters]

Environment

• OS Version: macOS
• Source or binary build? binary bottles, version 6.5.0 for example, since that formula uses -DBUILD_TESTING=OFF

Description

• Expected behavior: building with -DBUILD_TESTING=OFF should install the same files as with -DBUILD_TESTING=ON
• Actual behavior: COMMON_TEST_* executables are not built or installed when -DBUILD_TESTING=OFF

Steps to reproduce

1. Build gz-physics with -DBUILD_TESTING=OFF
2. make install
3. Check that libexec/gz/physics6/COMMON_TEST_* files are installed to the install prefix

Output

[scpeters]

we can fix this in our homebrew formulae fairly easily, but it may be something that we want to fix in the gz-physics cmake files