t9390: avoid using Bash-ism `<(...)`

The problem with this is that on Windows, we use the MSYS2 Bash which
uses the POSIX emulation layer called "MSYS2 runtime" that pretends that
there _is_ something like the `/dev/fd/` namespace, and tells `git.exe`
about it, but `git.exe` does not use the POSIX emulation layer, and
hence has no idea what Bash is talking about.

Besides, we should avoid pipes, just as we do in the Git project.

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

t/t9390-filter-repo.sh

@@ -917,7 +917,8 @@ test_expect_success '--strip-blobs-with-ids' '
 		grep fake_submodule ../filenames &&
 
 		# Strip "a certain file" files
-		git filter-repo --strip-blobs-with-ids <(echo deadbeefdeadbeefdeadbeefdeadbeefdeadbeef) &&
+		echo deadbeefdeadbeefdeadbeefdeadbeefdeadbeef >../input &&
+		git filter-repo --strip-blobs-with-ids ../input &&
 
 		git log --format=%n --name-only | sort | uniq >../filenames &&
 		test_line_count = 10 ../filenames &&
@@ -1232,10 +1233,12 @@ test_expect_success 'other startup error cases and requests for help' '
 		test_must_fail git filter-repo --path-rename foo:bar/ 2>err &&
 		test_i18ngrep "either ends with a slash then both must." err &&
 
-		test_must_fail git filter-repo --paths-from-file <(echo "foo==>bar/") 2>err &&
+		echo "foo==>bar/" >input &&
+		test_must_fail git filter-repo --paths-from-file input 2>err &&
 		test_i18ngrep "either ends with a slash then both must." err &&
 
-		test_must_fail git filter-repo --paths-from-file <(echo "glob:*.py==>newname") 2>err &&
+		echo "glob:*.py==>newname" >input &&
+		test_must_fail git filter-repo --paths-from-file input 2>err &&
 		test_i18ngrep "renaming globs makes no sense" err &&
 
 		test_must_fail git filter-repo --strip-blobs-bigger-than 3GiB 2>err &&
@@ -1358,7 +1361,8 @@ test_expect_success '--refs and --replace-text' '
 		git clone file://"$(pwd)"/path_rename refs_and_replace_text &&
 		cd refs_and_replace_text &&
 		git rev-parse --short=10 HEAD~1 >myparent &&
-		git filter-repo --force --replace-text <(echo "10==>TEN") --refs $(cat myparent)..master &&
+		echo "10==>TEN" >input &&
+		git filter-repo --force --replace-text input --refs $(cat myparent)..master &&
 		cat <<-EOF >expect &&
 		TEN11
 		EOF
@@ -1629,7 +1633,8 @@ test_expect_success 'degenerate merge with typechange' '
 		git ls-files >actual &&
 		test_cmp expect actual &&
 
-		test_line_count = 2 <(git log --oneline HEAD)
+		git log --oneline HEAD >input &&
+		test_line_count = 2 input
 	)
 '