Fix tests under GETTEXT_POISON on pack-object

Use the i18n-specific test functions in test scripts for pack-object.
This issue was was introduced in v1.7.10.2-556-g46140:

    46140 index-pack: use streaming interface for collision test on large blobs
    cf2ba pack-objects: use streaming interface for reading large loose blobs

and been broken under GETTEXT_POISON=YesPlease since.

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5300-pack-object.sh

@@ -416,11 +416,11 @@ test_expect_success \
 test_expect_success \
     'make sure index-pack detects the SHA1 collision' \
     'test_must_fail git index-pack -o bad.idx test-3.pack 2>msg &&
-     grep "SHA1 COLLISION FOUND" msg'
+     test_i18ngrep "SHA1 COLLISION FOUND" msg'
 
 test_expect_success \
     'make sure index-pack detects the SHA1 collision (large blobs)' \
     'test_must_fail git -c core.bigfilethreshold=1 index-pack -o bad.idx test-3.pack 2>msg &&
-     grep "SHA1 COLLISION FOUND" msg'
+     test_i18ngrep "SHA1 COLLISION FOUND" msg'
 
 test_done

t/t5530-upload-pack-error.sh

@@ -35,8 +35,8 @@ test_expect_success 'upload-pack fails due to error in pack-objects packing' '
 	printf "0032want %s\n00000009done\n0000" \
 		$(git rev-parse HEAD) >input &&
 	test_must_fail git upload-pack . <input >/dev/null 2>output.err &&
-	grep "unable to read" output.err &&
-	grep "pack-objects died" output.err
+	test_i18ngrep "unable to read" output.err &&
+	test_i18ngrep "pack-objects died" output.err
 '
 
 test_expect_success 'corrupt repo differently' '