Gimbal lock is a situation where the pitch (the middle angle) of the Tait-Bryan angles (usually called Euler angles incorrectly) is 90 degrees. If the angles specify a rotation close to gimbal lock, the precision requirements increase significantly, beyond what a single-precision float can provide, and at exactly gimbal lock, there's a loss of information. The test didn't take this into account. Fix this by decreasing the expected precision when close to gimbal lock.
The increased error rate on ARM Macs is probably caused by lesser precision in trigonometric functions. IEC-559 does not specify any semantics for those, and while Intel typically has a precision < 1 ulp for trigonometric functions with angles < 2*pi, it's likely that ARM's precision is a bit worse.
* Document Luanti rotation conventions
* Add test for setPitchYawRollRad (entity) rotation conventions
* Test and document that `vector.rotate` uses (extrinsic) Z-X-Y rotation order
