patch 8.1.1330: using bold attribute in terminal changes the color

Problem:    Using bold attribute in terminal changes the color. (Jason
            Franklin)
Solution:   Don't set the "bold-highbright" flag in vterm unless the terminal
            supports less than 16 colors.
diff --git a/src/testdir/dumps/Test_terminal_all_ansi_colors.dump b/src/testdir/dumps/Test_terminal_all_ansi_colors.dump
index 232f60d..57a085a 100644
--- a/src/testdir/dumps/Test_terminal_all_ansi_colors.dump
+++ b/src/testdir/dumps/Test_terminal_all_ansi_colors.dump
@@ -1,4 +1,4 @@
->A+0#0000001#8080809@1|B+0#e000002#ff404010@1|C+0#00e0003#40ff4011@1|D+0#e0e0004#ffff4012@1|E+0#0000e05#4040ff13@1|F+0#e000e06#ff40ff14@1|G+0#00e0e07#40ffff15@1|H+0#e0e0e08#ffffff16@1|I+0#8080809#0000001@1|J+0#ff404010#e000002@1|K+0#40ff4011#00e0003@1|L+0#ffff4012#e0e0004@1|M+0#4040ff13#0000e05@1|N+0#ff40ff14#e000e06@1|O+0#40ffff15#00e0e07@1|P+0#ffffff16#e0e0e08@1| +0#0000000#ffffff0@42
+>A+0#0000001#8080809@1|B+0#e000002#ff404010@1|C+0#00e0003#40ff4011@1|D+0#e0e0004#ffff4012@1|E+0#0000e05#4040ff13@1|F+0#e000e06#ff40ff14@1|G+0#00e0e07#40ffff15@1|H+0#e0e0e08#ffffff16@1|I+0#8080809#0000001@1|J+0#ff404010#e000002@1|K+0#40ff4011#00e0003@1|L+0#ffff4012#e0e0004@1|M+0#4040ff13#0000e05@1|N+0#ff40ff14#e000e06@1|O+0#40ffff15#00e0e07@1|P+0#ffffff16#e0e0e08@1| +0#0000000#ffffff0|X+2#e000002&@1|Y+2#40ff4011&@1|Z+2#ff40ff14#e000e06@1| +0#0000000#ffffff0@35
 @2| +0#4040ff13&@72
 |~| @73
 |~| @73
diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index 36e513e..fcad972 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -1491,7 +1491,7 @@
 
   " Use all the ANSI colors.
   call writefile([
-	\ 'call setline(1, "AABBCCDDEEFFGGHHIIJJKKLLMMNNOOPP")',
+	\ 'call setline(1, "AABBCCDDEEFFGGHHIIJJKKLLMMNNOOPP XXYYZZ")',
 	\ 'hi Tblack ctermfg=0 ctermbg=8',
 	\ 'hi Tdarkred ctermfg=1 ctermbg=9',
 	\ 'hi Tdarkgreen ctermfg=2 ctermbg=10',
@@ -1508,6 +1508,9 @@
 	\ 'hi Tmagenta ctermfg=13 ctermbg=5',
 	\ 'hi Tcyan ctermfg=14 ctermbg=6',
 	\ 'hi Twhite ctermfg=15 ctermbg=7',
+	\ 'hi TdarkredBold ctermfg=1 cterm=bold',
+	\ 'hi TgreenBold ctermfg=10 cterm=bold',
+	\ 'hi TmagentaBold ctermfg=13 cterm=bold ctermbg=5',
 	\ '',
 	\ 'call  matchadd("Tblack", "A")',
 	\ 'call  matchadd("Tdarkred", "B")',
@@ -1525,6 +1528,9 @@
 	\ 'call  matchadd("Tmagenta", "N")',
 	\ 'call  matchadd("Tcyan", "O")',
 	\ 'call  matchadd("Twhite", "P")',
+	\ 'call  matchadd("TdarkredBold", "X")',
+	\ 'call  matchadd("TgreenBold", "Y")',
+	\ 'call  matchadd("TmagentaBold", "Z")',
 	\ 'redraw',
 	\ ], 'Xcolorscript')
   let buf = RunVimInTerminal('-S Xcolorscript', {'rows': 10})