rename variable and add test directive for #58030

Author: pmccarter

src/librustc_mir/interpret/intrinsics.rs

@@ -139,8 +139,8 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                         // the fact that the operation has overflowed (if either is 0 no
                         // overflow can occur)
                         let first_term: u128 = l.to_scalar()?.to_bits(l.layout.size)?;
-                        let first_term_pos = first_term & (1 << (num_bits-1)) == 0;
-                        if first_term_pos {
+                        let first_term_positive = first_term & (1 << (num_bits-1)) == 0;
+                        if first_term_positive {
                             // Negative overflow not possible since the positive first term
                             // can only increase an (in range) negative term for addition
                             // or corresponding negated positive term for subtraction

src/test/run-pass/const-int-saturating-arith.rs

@@ -1,3 +1,4 @@
+// ignore-emscripten no i128 support
 #![feature(const_saturating_int_methods)]
 
 const INT_U32_NO: u32 = (42 as u32).saturating_add(2);