revert(3p/git): Revert merge of git upstream at v2.26.2

This causes cgit to serve error pages, which is undesirable.

This reverts commit 5229c9b232, reversing
changes made to f2b211131f.

third_party/git/t/lib-log-graph.sh

@@ -1,28 +0,0 @@
-# Helps shared by the test scripts for comparing log graphs.
-
-sanitize_log_output () {
-	sed -e 's/ *$//' \
-	    -e 's/commit [0-9a-f]*$/commit COMMIT_OBJECT_NAME/' \
-	    -e 's/Merge: [ 0-9a-f]*$/Merge: MERGE_PARENTS/' \
-	    -e 's/Merge tag.*/Merge HEADS DESCRIPTION/' \
-	    -e 's/Merge commit.*/Merge HEADS DESCRIPTION/' \
-	    -e 's/index [0-9a-f]*\.\.[0-9a-f]*/index BEFORE..AFTER/'
-}
-
-lib_test_cmp_graph () {
-	git log --graph "$@" >output &&
-	sed 's/ *$//' >output.sanitized <output &&
-	test_i18ncmp expect output.sanitized
-}
-
-lib_test_cmp_short_graph () {
-	git log --graph --pretty=short "$@" >output &&
-	sanitize_log_output >output.sanitized <output &&
-	test_i18ncmp expect output.sanitized
-}
-
-lib_test_cmp_colored_graph () {
-	git log --graph --color=always "$@" >output.colors.raw &&
-	test_decode_color <output.colors.raw | sed "s/ *\$//" >output.colors &&
-	test_cmp expect.colors output.colors
-}