patch 8.2.1637: Vim9: :put ={expr} does not work inside :def function

Problem:    Vim9: :put ={expr} does not work inside :def function.
Solution:   Add ISN_PUT. (closes #6397)
diff --git a/src/testdir/test_vim9_disassemble.vim b/src/testdir/test_vim9_disassemble.vim
index b738f19..1582f12 100644
--- a/src/testdir/test_vim9_disassemble.vim
+++ b/src/testdir/test_vim9_disassemble.vim
@@ -118,6 +118,21 @@
         res)
 enddef
 
+def s:PutExpr()
+  :3put ="text"
+enddef
+
+def Test_disassemble_put_expr()
+  let res = execute('disass s:PutExpr')
+  assert_match('<SNR>\d*_PutExpr.*' ..
+        ' :3put ="text"\_s*' ..
+        '\d PUSHS "text"\_s*' ..
+        '\d PUT = 3\_s*' ..
+        '\d PUSHNR 0\_s*' ..
+        '\d RETURN',
+        res)
+enddef
+
 def s:ScriptFuncPush()
   let localbool = true
   let localspec = v:none