vim-patch:8.2.3908: cannot use a script-local function for 'foldtext'

Problem:    Cannot use a script-local function for 'foldtext'.
Solution:   Expand "s:" and "<SID>". (Yegappan Lakshmanan, closes vim/vim#9411)

27708e6c7b

Cherry-pick test_filter_map.vim change from patch 8.2.3871.

Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>

test/old/testdir/test_blob.vim

@@ -38,6 +38,7 @@ func Test_blob_create()
       call assert_fails('VAR b = 0z001122.')
       call assert_fails('call get("", 1)', 'E896:')
       call assert_equal(0, len(v:_null_blob))
+      call assert_equal(0z, copy(v:_null_blob))
   END
   call CheckLegacyAndVim9Success(lines)
 endfunc
@@ -370,6 +371,14 @@ func Test_blob_add()
       add(v:_null_blob, 0x22)
   END
   call CheckDefExecAndScriptFailure(lines, 'E1131:')
+
+  let lines =<< trim END
+      let b = 0zDEADBEEF
+      lockvar b
+      call add(b, 0)
+      unlockvar b
+  END
+  call CheckScriptFailure(lines, 'E741:')
 endfunc
 
 func Test_blob_empty()
@@ -464,6 +473,9 @@ func Test_blob_func_remove()
       remove(b, 0)
   END
   call CheckScriptFailure(lines, 'E741:')
+
+  call assert_fails('echo remove(0z1020, [])', 'E745:')
+  call assert_fails('echo remove(0z1020, 0, [])', 'E745:')
 endfunc
 
 func Test_blob_read_write()
@@ -524,6 +536,7 @@ func Test_blob_filter()
       call assert_equal(0zADEF, filter(0zDEADBEEF, 'v:key % 2'))
   END
   call CheckLegacyAndVim9Success(lines)
+  call assert_fails('echo filter(0z10, "a10")', 'E121:')
 endfunc
 
 " map() item in blob
@@ -539,6 +552,7 @@ func Test_blob_map()
       call map(0z00, '[9]')
   END
   call CheckLegacyAndVim9Failure(lines, 'E978:')
+  call assert_fails('echo map(0z10, "a10")', 'E121:')
 endfunc
 
 func Test_blob_index()