Fix a number of tests to work correctly with 32/64-wide targets.

Still to be reviewed/fixed: tests/test-*, tests/[cfrs]*

tests/local-atomics-12.ispc

@@ -6,14 +6,14 @@ uniform unsigned int32 s = 0;
 export void f_f(uniform float RET[], uniform float aFOO[]) {
     float a = aFOO[programIndex]; 
     float b = 0;
-    if (programIndex & 1)
+    if (programIndex < 29 && (programIndex & 1))
         b = atomic_or_local(&s, (1 << programIndex));
     RET[programIndex] = s;
 }
 
 export void result(uniform float RET[]) {
     uniform int sum = 0;
-    for (uniform int i = 0; i < programCount; ++i)
+    for (uniform int i = 0; i < min(programCount, 29); ++i)
         if (i & 1)
             sum += (1 << i);
     RET[programIndex] = sum;