Change tex_adr type to mjtSize.

Adds a test which verifies that we can index into the texture buffer at offsets larger than can be represented by a 32-bit signed int.

PiperOrigin-RevId: 868756646
Change-Id: Ibc1a2b269fce41aec370611b0aab77803837e7a8

wasm/tests/bindings_test.ts

@@ -2163,9 +2163,10 @@ describe('MuJoCo WASM Bindings', () => {
       try {
         assertExists(model);
         const t1 = model.tex('t1');
+        const texAdr = Number(model.tex_adr[t1.id]);
         const expectedData = model.tex_data.slice(
-            model.tex_adr[t1.id],
-            model.tex_adr[t1.id] +
+            texAdr,
+            texAdr +
                 model.tex_height[t1.id] * model.tex_width[t1.id] *
                     model.tex_nchannel[t1.id]);