Add compiler timing diagnostics to mjsCompiler, printed by compile.cc

For example, `compile mujoco_menagerie/robotis_op3/scene.xml` now outputs

```
Compile 1 (cold cache):
  total:      317.2 ms
  assets:     284.8 ms (wall clock)
    load:     616.1 ms
    hull:      26.4 ms
    poly:     137.8 ms
    inert:    177.8 ms
    bvh:      568.2 ms
    octr:       1.6 ms
    tex:       25.3 ms
  other:       32.4 ms

Compile 2 (warm cache):
  total:       79.9 ms
  assets:      54.5 ms (wall clock)
    load:     888.5 ms
    hull:       0.0 ms
    poly:       0.0 ms
    inert:      0.0 ms
    bvh:        0.0 ms
    octr:       0.0 ms
    tex:       21.4 ms
  other:       25.3 ms
```

PiperOrigin-RevId: 917850214
Change-Id: Iaec86230bec0faf2e47820e20cbff61de5b2621e

python/mujoco/introspect/functions.py

@@ -6471,6 +6471,22 @@ FUNCTIONS: Mapping[str, FunctionDecl] = dict([
          ),
          doc='Get compiler error message from spec.',
      )),
+    ('mjs_getTimer',
+     FunctionDecl(
+         name='mjs_getTimer',
+         return_type=PointerType(
+             inner_type=ValueType(name='double', is_const=True),
+         ),
+         parameters=(
+             FunctionParameterDecl(
+                 name='s',
+                 type=PointerType(
+                     inner_type=ValueType(name='mjSpec'),
+                 ),
+             ),
+         ),
+         doc='Get compiler timing diagnostics from spec, returns pointer to array of size mjNCTIMER.',  # pylint: disable=line-too-long
+     )),
     ('mjs_isWarning',
      FunctionDecl(
          name='mjs_isWarning',