patch 8.1.1170: terminal ANSI color test does not cover all colors

Problem:    Terminal ANSI color test does not cover all colors.
Solution:   Use the color number, the name is not always resulting in an ANSI
            color when t_Co is 256.
diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index f81bcd3..be771b4 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -1492,22 +1492,22 @@
   " Use all the ANSI colors.
   call writefile([
 	\ 'call setline(1, "AABBCCDDEEFFGGHHIIJJKKLLMMNNOOPP")',
-	\ 'hi Tblack ctermfg=Black ctermbg=Lightgrey',
-	\ 'hi Tdarkred ctermfg=Darkred ctermbg=Red',
-	\ 'hi Tdarkgreen ctermfg=Darkgreen ctermbg=Green',
-	\ 'hi Tbrown ctermfg=Brown ctermbg=Yellow',
-	\ 'hi Tdarkblue ctermfg=Darkblue ctermbg=Blue',
-	\ 'hi Tdarkmagenta ctermfg=Darkmagenta ctermbg=Magenta',
-	\ 'hi Tdarkcyan ctermfg=Darkcyan ctermbg=Cyan',
-	\ 'hi Tlightgrey ctermfg=Lightgrey ctermbg=Black',
-	\ 'hi Tdarkgrey ctermfg=Darkgrey ctermbg=White',
-	\ 'hi Tred ctermfg=Red ctermbg=Darkred',
-	\ 'hi Tgreen ctermfg=Green ctermbg=Darkgreen',
-	\ 'hi Tyellow ctermfg=Yellow ctermbg=Brown',
-	\ 'hi Tblue ctermfg=Blue ctermbg=Darkblue',
-	\ 'hi Tmagenta ctermfg=Magenta ctermbg=Darkmagenta',
-	\ 'hi Tcyan ctermfg=Cyan ctermbg=Darkcyan',
-	\ 'hi Twhite ctermfg=White ctermbg=Darkgrey',
+	\ 'hi Tblack ctermfg=0 ctermbg=8',
+	\ 'hi Tdarkred ctermfg=1 ctermbg=9',
+	\ 'hi Tdarkgreen ctermfg=2 ctermbg=10',
+	\ 'hi Tbrown ctermfg=3 ctermbg=11',
+	\ 'hi Tdarkblue ctermfg=4 ctermbg=12',
+	\ 'hi Tdarkmagenta ctermfg=5 ctermbg=13',
+	\ 'hi Tdarkcyan ctermfg=6 ctermbg=14',
+	\ 'hi Tlightgrey ctermfg=7 ctermbg=15',
+	\ 'hi Tdarkgrey ctermfg=8 ctermbg=0',
+	\ 'hi Tred ctermfg=9 ctermbg=1',
+	\ 'hi Tgreen ctermfg=10 ctermbg=2',
+	\ 'hi Tyellow ctermfg=11 ctermbg=3',
+	\ 'hi Tblue ctermfg=12 ctermbg=4',
+	\ 'hi Tmagenta ctermfg=13 ctermbg=5',
+	\ 'hi Tcyan ctermfg=14 ctermbg=6',
+	\ 'hi Twhite ctermfg=15 ctermbg=7',
 	\ '',
 	\ 'call  matchadd("Tblack", "A")',
 	\ 'call  matchadd("Tdarkred", "B")',