Tests (MinGW): Do not bother to test funny file names

MSys2 actually allows to create files or directories whose names contain
tabs, newlines or colors, even if plain Win32 API cannot access them.
As we are using an MSys2 bash to run the tests, such files or
directories are created successfully, but Git has no chance to work with
them because it is a regular Windows program, hence limited by the Win32
API.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

t/t3300-funny-names.sh

@@ -13,6 +13,7 @@ tree, index, and tree objects.
 
 HT='	'
 
+test_have_prereq MINGW ||
 echo 2>/dev/null > "Name with an${HT}HT"
 if ! test -f "Name with an${HT}HT"
 then

t/t3600-rm.sh

@@ -14,7 +14,8 @@ test_expect_success \
      git add -- foo bar baz 'space embedded' -q &&
      git commit -m 'add normal files'"
 
-if touch -- 'tab	embedded' 'newline
+
+if ! test_have_prereq MINGW && touch -- 'tab	embedded' 'newline
 embedded' 2>/dev/null
 then
 	test_set_prereq FUNNYNAMES

t/t3703-add-magic-pathspec.sh

@@ -38,7 +38,7 @@ cat >expected <<EOF
 add 'sub/foo'
 EOF
 
-if mkdir ":" 2>/dev/null
+if ! test_have_prereq MINGW && mkdir ":" 2>/dev/null
 then
 	test_set_prereq COLON_DIR
 fi

t/t3902-quoted.sh

@@ -12,6 +12,7 @@ GN='純'
 HT='	'
 DQ='"'
 
+test_have_prereq MINGW ||
 echo foo 2>/dev/null > "Name and an${HT}HT"
 if ! test -f "Name and an${HT}HT"
 then

t/t4016-diff-quote.sh

@@ -13,6 +13,7 @@ P1='pathname	with HT'
 P2='pathname with SP'
 P3='pathname
 with LF'
+test_have_prereq !MINGW &&
 echo 2>/dev/null >"$P1" && test -f "$P1" && rm -f "$P1" || {
 	skip_all='Your filesystem does not allow tabs in filenames'
 	test_done

t/t4135-apply-weird-filenames.sh

@@ -19,7 +19,8 @@ test_expect_success 'setup' '
 
 	test_when_finished "rm -f \"tab	embedded.txt\"" &&
 	test_when_finished "rm -f '\''\"quoteembedded\".txt'\''" &&
-	if touch -- "tab	embedded.txt" '\''"quoteembedded".txt'\''
+	if ! test_have_prereq MINGW &&
+		touch -- "tab	embedded.txt" '\''"quoteembedded".txt'\''
 	then
 		test_set_prereq FUNNYNAMES
 	fi

t/t9903-bash-prompt.sh

@@ -67,7 +67,7 @@ repo_with_newline='repo
 with
 newline'
 
-if mkdir "$repo_with_newline" 2>/dev/null
+if ! test_have_prereq MINGW && mkdir "$repo_with_newline" 2>/dev/null
 then
 	test_set_prereq FUNNYNAMES
 else