patch 8.2.3310: Vim9: unpack assignment does not mention source of type error

Problem:    Vim9: unpack assignment does not mention source of type error.
Solution:   Mention the argument number. (closes #8719)
diff --git a/src/testdir/test_vim9_disassemble.vim b/src/testdir/test_vim9_disassemble.vim
index 253fe1b..9eaa864 100644
--- a/src/testdir/test_vim9_disassemble.vim
+++ b/src/testdir/test_vim9_disassemble.vim
@@ -441,10 +441,10 @@
         '\d CHECKTYPE list<any> stack\[-1\]\_s*' ..
         '\d CHECKLEN >= 2\_s*' ..
         '\d\+ ITEM 0\_s*' ..
-        '\d\+ CHECKTYPE string stack\[-1\]\_s*' ..
+        '\d\+ CHECKTYPE string stack\[-1\] arg 1\_s*' ..
         '\d\+ STORE $0\_s*' ..
         '\d\+ ITEM 1\_s*' ..
-        '\d\+ CHECKTYPE string stack\[-1\]\_s*' ..
+        '\d\+ CHECKTYPE string stack\[-1\] arg 2\_s*' ..
         '\d\+ STORE $1\_s*' ..
         '\d\+ SLICE 2\_s*' ..
         '\d\+ STORE $2\_s*' ..