[codegen] add intcc conditions for reading carry flag

Add conditions to IntCC for checking the carry flag (Carry, NotCarry).

Fixes: https://github.com/CraneStation/cranelift/issues/980

cranelift/codegen/src/legalizer/heap.rs

@@ -83,7 +83,11 @@ fn dynamic_addr(
         // We need an overflow check for the adjusted offset.
         let access_size_val = pos.ins().iconst(offset_ty, access_size as i64);
         let (adj_offset, overflow) = pos.ins().iadd_ifcout(offset, access_size_val);
-        pos.ins().trapnz(overflow, ir::TrapCode::HeapOutOfBounds);
+        pos.ins().trapif(
+            isa.unsigned_add_overflow_condition(),
+            overflow,
+            ir::TrapCode::HeapOutOfBounds,
+        );
         oob = pos
             .ins()
             .icmp(IntCC::UnsignedGreaterThan, adj_offset, bound);