test-lib-functions: remove generate_zero_bytes() wrapper

Since d5cfd14 (tests: teach the test-tool to generate NUL bytes
and use it, 2019-02-14) the generate_zero_bytes() functions has been a
thin wrapper for "test-tool genzeros". Let's have its only user call
that directly instead.

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

t/t5318-commit-graph.sh

@@ -529,7 +529,7 @@ corrupt_graph_and_verify() {
 	zero_pos=${4:-${orig_size}} &&
 	printf "$data" | dd of="$objdir/info/commit-graph" bs=1 seek="$pos" conv=notrunc &&
 	dd of="$objdir/info/commit-graph" bs=1 seek="$zero_pos" if=/dev/null &&
-	generate_zero_bytes $(($orig_size - $zero_pos)) >>"$objdir/info/commit-graph" &&
+	test-tool genzeros $(($orig_size - $zero_pos)) >>"$objdir/info/commit-graph" &&
 	corrupt_graph_verify "$grepstr"
 
 }

t/test-lib-functions.sh

@@ -111,13 +111,6 @@ remove_cr () {
 	tr '\015' Q | sed -e 's/Q$//'
 }
 
-# Generate an output of $1 bytes of all zeroes (NULs, not ASCII zeroes).
-# If $1 is 'infinity', output forever or until the receiving pipe stops reading,
-# whichever comes first.
-generate_zero_bytes () {
-	test-tool genzeros "$@"
-}
-
 # In some bourne shell implementations, the "unset" builtin returns
 # nonzero status when a variable to be unset was not set in the first
 # place.