[vm/ffi] Wrong error message for Array boundaries check

[sgrekhov]

import "dart:ffi";

class Struct8BytesInlineArrayInt extends Struct {
  @Array(8)
  external Array<Uint8> a0;
}

void main() {
  final pointer = calloc<Struct8BytesInlineArrayInt>();
  final array = pointer.ref.a0;
  array[8]; // RangeError: Invalid value: Not in inclusive range 0..8: 8
}

Error message here is wrong. Valid range here is 0..7

Dart SDK version: 2.13.0-edge.dcd57353459f85beb7bbe415a452c54fd6e9833a (be) (Tue Mar 2 00:10:50 2021 +0000) on "windows_x64"