Fix expected diagnostic in acle_sme2_imm.cpp test

Author: CarolineConcatto

clang/test/Sema/aarch64-sme2-intrinsics/acle_sme2_imm.cpp

@@ -361,6 +361,6 @@ void test_read_zt() __arm_streaming __arm_inout("zt0") {
   svwrite_lane_zt(1, svundef_s8(), 1);  // expected-error {{argument value 1 is outside the valid range [0, 0]}}
   svwrite_zt(1, svundef_s8());          // expected-error {{argument value 1 is outside the valid range [0, 0]}}
   // Check index
-  svwrite_lane_zt(0, svundef_s8(), 0);  // expected-error {{argument value 4 is outside the valid range [1, 3]}}
+  svwrite_lane_zt(0, svundef_s8(), 0);  // expected-error {{argument value 0 is outside the valid range [1, 3]}}
   svwrite_lane_zt(0, svundef_s8(), 4);  // expected-error {{argument value 4 is outside the valid range [1, 3]}}
 }