tests: avoid calling Perl just to determine file sizes

It is a bit ridiculous to spin up a full-blown Perl instance (especially
on Windows, where that means spinning up a full POSIX emulation layer,
AKA the MSYS2 runtime) just to tell how large a given file is.

So let's just use the test-tool to do that job instead.

This command will also be used over the next commits, to allow for
cutting out individual test cases' verbose log from the file generated
via --verbose-log.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/helper/test-path-utils.c

@@ -291,6 +291,18 @@ int cmd__path_utils(int argc, const char **argv)
 		return !!res;
 	}
 
+	if (argc > 2 && !strcmp(argv[1], "file-size")) {
+		int res = 0, i;
+		struct stat st;
+
+		for (i = 2; i < argc; i++)
+			if (stat(argv[i], &st))
+				res = error_errno("Cannot stat '%s'", argv[i]);
+			else
+				printf("%"PRIuMAX"\n", (uintmax_t)st.st_size);
+		return !!res;
+	}
+
 	fprintf(stderr, "%s: unknown function name: %s\n", argv[0],
 		argv[1] ? argv[1] : "(there was none)");
 	return 1;

t/t0021-conversion.sh

@@ -24,7 +24,7 @@ generate_random_characters () {
 }
 
 file_size () {
-	perl -e 'print -s $ARGV[0]' "$1"
+	test-tool path-utils file-size "$1"
 }
 
 filter_git () {

t/t1050-large.sh

@@ -8,7 +8,7 @@ test_description='adding and checking out large blobs'
 # This should be moved to test-lib.sh together with the
 # copy in t0021 after both topics have graduated to 'master'.
 file_size () {
-	perl -e 'print -s $ARGV[0]' "$1"
+	test-tool path-utils file-size "$1"
 }
 
 test_expect_success setup '

t/t5315-pack-objects-compression.sh

@@ -7,7 +7,7 @@ test_description='pack-object compression configuration'
 # This should be moved to test-lib.sh together with the
 # copy in t0021 after both topics have graduated to 'master'.
 file_size () {
-	perl -e 'print -s $ARGV[0]' "$1"
+	test-tool path-utils file-size "$1"
 }
 
 test_expect_success setup '

t/t9303-fast-import-compression.sh

@@ -6,7 +6,7 @@ test_description='compression setting of fast-import utility'
 # This should be moved to test-lib.sh together with the
 # copy in t0021 after both topics have graduated to 'master'.
 file_size () {
-	perl -e 'print -s $ARGV[0]' "$1"
+	test-tool path-utils file-size "$1"
 }
 
 import_large () {