patch 8.0.0708: some tests are old style

Problem:    Some tests are old style.
Solution:   Change a few tests from old style to new style. (pschuh,
            closes #1813)
diff --git a/src/testdir/test_maparg.vim b/src/testdir/test_maparg.vim
new file mode 100644
index 0000000..9ad8383
--- /dev/null
+++ b/src/testdir/test_maparg.vim
@@ -0,0 +1,52 @@
+" Tests for maparg().
+" Also test utf8 map with a 0x80 byte.
+if !has("multi_byte")
+  finish
+endif
+
+function s:SID()     
+  return str2nr(matchstr(expand('<sfile>'), '<SNR>\zs\d\+\ze_SID$'))
+endfun
+
+function Test_maparg()
+  new
+  set cpo-=<
+  set encoding=utf8
+  " Test maparg() with a string result
+  map foo<C-V> is<F4>foo
+  vnoremap <script> <buffer> <expr> <silent> bar isbar
+  let sid = s:SID()
+  call assert_equal("is<F4>foo", maparg('foo<C-V>'))
+  call assert_equal({'silent': 0, 'noremap': 0, 'lhs': 'foo<C-V>',
+        \ 'mode': ' ', 'nowait': 0, 'expr': 0, 'sid': sid, 'rhs': 'is<F4>foo',
+        \ 'buffer': 0}, maparg('foo<C-V>', '', 0, 1))
+  call assert_equal({'silent': 1, 'noremap': 1, 'lhs': 'bar', 'mode': 'v',
+        \ 'nowait': 0, 'expr': 1, 'sid': sid, 'rhs': 'isbar', 'buffer': 1},
+        \ maparg('bar', '', 0, 1))
+  map <buffer> <nowait> foo bar
+  call assert_equal({'silent': 0, 'noremap': 0, 'lhs': 'foo', 'mode': ' ',
+        \ 'nowait': 1, 'expr': 0, 'sid': sid, 'rhs': 'bar', 'buffer': 1},
+        \ maparg('foo', '', 0, 1))
+
+  map abc x<char-114>x
+  call assert_equal(maparg('abc'), "xrx")
+  map abc y<S-char-114>y
+  call assert_equal(maparg('abc'), "yRy")
+endfunction
+
+function Test_range_map()
+  new
+  " Outside of the range, minimum
+  inoremap <Char-0x1040> a
+  execute "normal a\u1040\<Esc>"
+  " Inside of the range, minimum
+  inoremap <Char-0x103f> b
+  execute "normal a\u103f\<Esc>"
+  " Inside of the range, maximum
+  inoremap <Char-0xf03f> c
+  execute "normal a\uf03f\<Esc>"
+  " Outside of the range, maximum
+  inoremap <Char-0xf040> d
+  execute "normal a\uf040\<Esc>"
+  call assert_equal("abcd", getline(1))
+endfunction