This is a no-op "prefactor" of `mj_crb` to reduce the number of lines changed in the upcoming sleeping CL. The main change here is that `mj_crb` now avoids accessing the model and data pointer repeatedly, but instead has the input and output pointers explicitly declared as local variables. A benchmark test found a healthy **14% perf bump** due to two changes:
- Adding `restrict` to `mju_mulInertVec`
- The function-local pointers.
Adding `restrict` to the local pointers had no effect. Note that `mj_crb` is not a particularly expensive function so these speed bumps are not significant per se, but rather indicative of possible future gains with these techniques.
```
Benchmark Time(ns) CPU(ns) Iterations
---------------------------------------------------------------
ORGINAL BASELINE
BM_CRB_BASELINE_mean 4325 4348 993200 230.052k items/s
BASELINE + RESTRICT
BM_CRB_BASELINE_mean 4057 4090 1186150 244.573k items/s
LOCAL POINTERS + RESTRICT
BM_CRB_mean 3772 3800 1001750 263.209k items/s
```
PiperOrigin-RevId: 815798225
Change-Id: Iffdf57b544e8e10562807c617f73ca4ccd1c614f
Yuval Tassa