t7700: update to work with MIDX bitmap test knob

A number of these tests are focused only on pack-based bitmaps and need
to be updated to disable 'GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP' where
necessary.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t7700-repack.sh

@@ -63,12 +63,13 @@ test_expect_success 'objects in packs marked .keep are not repacked' '
 
 test_expect_success 'writing bitmaps via command-line can duplicate .keep objects' '
 	# build on $oid, $packid, and .keep state from previous
-	git repack -Adbl &&
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 git repack -Adbl &&
 	test_has_duplicate_object true
 '
 
 test_expect_success 'writing bitmaps via config can duplicate .keep objects' '
 	# build on $oid, $packid, and .keep state from previous
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
 		git -c repack.writebitmaps=true repack -Adl &&
 	test_has_duplicate_object true
 '
@@ -189,6 +190,8 @@ test_expect_success 'repack --keep-pack' '
 
 test_expect_success 'bitmaps are created by default in bare repos' '
 	git clone --bare .git bare.git &&
+	rm -f bare.git/objects/pack/*.bitmap &&
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
 		git -C bare.git repack -ad &&
 	bitmap=$(ls bare.git/objects/pack/*.bitmap) &&
 	test_path_is_file "$bitmap"
@@ -200,6 +203,7 @@ test_expect_success 'incremental repack does not complain' '
 '
 
 test_expect_success 'bitmaps can be disabled on bare repos' '
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
 		git -c repack.writeBitmaps=false -C bare.git repack -ad &&
 	bitmap=$(ls bare.git/objects/pack/*.bitmap || :) &&
 	test -z "$bitmap"
@@ -211,6 +215,7 @@ test_expect_success 'no bitmaps created if .keep files present' '
 	keep=${pack%.pack}.keep &&
 	test_when_finished "rm -f \"\$keep\"" &&
 	>"$keep" &&
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
 		git -C bare.git repack -ad 2>stderr &&
 	test_must_be_empty stderr &&
 	find bare.git/objects/pack/ -type f -name "*.bitmap" >actual &&
@@ -222,6 +227,7 @@ test_expect_success 'auto-bitmaps do not complain if unavailable' '
 	blob=$(test-tool genrandom big $((1024*1024)) |
 	       git -C bare.git hash-object -w --stdin) &&
 	git -C bare.git update-ref refs/tags/big $blob &&
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
 		git -C bare.git repack -ad 2>stderr &&
 	test_must_be_empty stderr &&
 	find bare.git/objects/pack -type f -name "*.bitmap" >actual &&