[TEST ONLY] Break RV64 backend

Just to check that the tests will fail...

Signed-off-by: Hanno Becker <beckphan@amazon.co.uk>

Author: hanno-becker

mlkem/native/riscv64/src/rv64v_poly.c

@@ -90,7 +90,11 @@ static inline vint16m1_t fq_mul_vv(vint16m1_t rx, vint16m1_t ry, size_t vl)
   vint16m1_t rl, rh;
 
   rh = __riscv_vmulh_vv_i16m1(rx, ry, vl); /*  h = (x * y) / R */
-  rl = __riscv_vmul_vv_i16m1(rx, ry, vl);  /*  l = (x * y) % R */
+  /* !!! DELIBERATELY BREAKING !!! */
+  /* ONLY FOR TEST */
+  rl = __riscv_vmul_vv_i16m1(rx, rx, vl); /*  l = (x * y) % R */
+  /* CORRECT LINE */
+  /* rl = __riscv_vmul_vv_i16m1(rx, ry, vl);  */ /*  l = (x * y) % R */
   return fq_redc(rh, rl, vl);
 #else  /* !MLK_RVV_WIDENING_MUL */
   return fq_redc2(__riscv_vwmul_vv_i32m2(rx, ry, vl), vl);