patch 8.1.2264: there are two test files for :let

Problem:    There are two test files for :let.
Solution:   Merge the two files.
diff --git a/src/testdir/Make_all.mak b/src/testdir/Make_all.mak
index f3906ac..6b86b37 100644
--- a/src/testdir/Make_all.mak
+++ b/src/testdir/Make_all.mak
@@ -58,7 +58,6 @@
 	test_arabic \
 	test_arglist \
 	test_assert \
-	test_assign \
 	test_autochdir \
 	test_autocmd \
 	test_autoload \
diff --git a/src/testdir/test_alot.vim b/src/testdir/test_alot.vim
index 216ff6c..894ec58 100644
--- a/src/testdir/test_alot.vim
+++ b/src/testdir/test_alot.vim
@@ -1,7 +1,6 @@
 " A series of tests that can run in one Vim invocation.
 " This makes testing go faster, since Vim doesn't need to restart.
 
-source test_assign.vim
 source test_backup.vim
 source test_behave.vim
 source test_bufline.vim
diff --git a/src/testdir/test_assign.vim b/src/testdir/test_assign.vim
deleted file mode 100644
index 1715a3f..0000000
--- a/src/testdir/test_assign.vim
+++ /dev/null
@@ -1,53 +0,0 @@
-" Test for assignment
-
-func Test_no_type_checking()
-  let v = 1
-  let v = [1,2,3]
-  let v = {'a': 1, 'b': 2}
-  let v = 3.4
-  let v = 'hello'
-endfunc
-
-func Test_let_termcap()
-  " Terminal code
-  let old_t_te = &t_te
-  let &t_te = "\<Esc>[yes;"
-  call assert_match('t_te.*^[[yes;', execute("set termcap"))
-  let &t_te = old_t_te
-
-  if exists("+t_k1")
-    " Key code
-    let old_t_k1 = &t_k1
-    let &t_k1 = "that"
-    call assert_match('t_k1.*that', execute("set termcap"))
-    let &t_k1 = old_t_k1
-  endif
-
-  call assert_fails('let x = &t_xx', 'E113')
-  let &t_xx = "yes"
-  call assert_equal("yes", &t_xx)
-  let &t_xx = ""
-  call assert_fails('let x = &t_xx', 'E113')
-endfunc
-
-func Test_let_option_error()
-  let _w = &tw
-  let &tw = 80
-  call assert_fails('let &tw .= 1', 'E734')
-  call assert_equal(80, &tw)
-  let &tw = _w
-
-  let _w = &fillchars
-  let &fillchars = "vert:|"
-  call assert_fails('let &fillchars += "diff:-"', 'E734')
-  call assert_equal("vert:|", &fillchars)
-  let &fillchars = _w
-endfunc
-
-func Test_let_errors()
-  let s = 'abcd'
-  call assert_fails('let s[1] = 5', 'E689:')
-
-  let l = [1, 2, 3]
-  call assert_fails('let l[:] = 5', 'E709:')
-endfunc
diff --git a/src/testdir/test_let.vim b/src/testdir/test_let.vim
index 76b7505..4d9aae9 100644
--- a/src/testdir/test_let.vim
+++ b/src/testdir/test_let.vim
@@ -152,6 +152,58 @@
   call assert_equal('ĀĒĪŌŪあいうえお', $a)
 endfunc
 
+func Test_let_no_type_checking()
+  let v = 1
+  let v = [1,2,3]
+  let v = {'a': 1, 'b': 2}
+  let v = 3.4
+  let v = 'hello'
+endfunc
+
+func Test_let_termcap()
+  " Terminal code
+  let old_t_te = &t_te
+  let &t_te = "\<Esc>[yes;"
+  call assert_match('t_te.*^[[yes;', execute("set termcap"))
+  let &t_te = old_t_te
+
+  if exists("+t_k1")
+    " Key code
+    let old_t_k1 = &t_k1
+    let &t_k1 = "that"
+    call assert_match('t_k1.*that', execute("set termcap"))
+    let &t_k1 = old_t_k1
+  endif
+
+  call assert_fails('let x = &t_xx', 'E113')
+  let &t_xx = "yes"
+  call assert_equal("yes", &t_xx)
+  let &t_xx = ""
+  call assert_fails('let x = &t_xx', 'E113')
+endfunc
+
+func Test_let_option_error()
+  let _w = &tw
+  let &tw = 80
+  call assert_fails('let &tw .= 1', 'E734')
+  call assert_equal(80, &tw)
+  let &tw = _w
+
+  let _w = &fillchars
+  let &fillchars = "vert:|"
+  call assert_fails('let &fillchars += "diff:-"', 'E734')
+  call assert_equal("vert:|", &fillchars)
+  let &fillchars = _w
+endfunc
+
+func Test_let_errors()
+  let s = 'abcd'
+  call assert_fails('let s[1] = 5', 'E689:')
+
+  let l = [1, 2, 3]
+  call assert_fails('let l[:] = 5', 'E709:')
+endfunc
+
 func Test_let_heredoc_fails()
   call assert_fails('let v =<< marker', 'E991:')
 
diff --git a/src/version.c b/src/version.c
index fe0d805..8dcefd4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2264,
+/**/
     2263,
 /**/
     2262,