lib: split bytes tests into equal/index/contains/tokenize/trim per ref/hare/bytes

Pure move: bytes_test.ww dissolves along its banner seams into sibling
equal_test.ww, index_test.ww (u8 + []u8 arms of index/rindex),
contains_test.ww (contains/hasprefix/hassuffix), tokenize_test.ww
(tokenize/rtokenize/peektoken/remainingtokens + splitn/rsplitn/split +
cut/rcut), and trim_test.ww, mirroring ref/hare/bytes/{equal,index,
contains,tokenize,trim}.ha ownership (Hare keeps splitn and cut in
tokenize.ha; contains.ha owns hasprefix/hassuffix). Blocks are
byte-identical; only the banner lines are deleted. Helpers stay with
their sole consumers: expect_token/expect_done/expect_tok in
tokenize_test.ww, beq in trim_test.ww.

Consumers: Makefile LIBRARY_TESTS replaces the bytes_test.ww entry
with the five new entries at the same position; the
test/byteid/libbyteid_test.ww roster row becomes five fx rows,
NENTEXPECT 48->52 (+4).

lib/bytes/contains_test.ww

@@ -0,0 +1,59 @@
+// containstest — exercises bytes.contains/hasprefix/hassuffix. A
+// failing row aborts via the assert/abort builtin (task #5 @test
+// conversion). Vectors mirror ref/hare/bytes/contains.ha.
+
+package bytes_test;
+
+import bytes;
+
+@test fn contains_cases() void = {
+	let a: [4]u8; a[0] = 1u8; a[1] = 3u8; a[2] = 3u8; a[3] = 7u8;
+	assert(!(!bytes.contains(a[0:4], 7u8)));
+	assert(!( bytes.contains(a[0:4], 42u8)));
+	let n: [2]u8; n[0] = 3u8; n[1] = 3u8;
+	assert(!(!bytes.contains(a[0:4], n[0:2])));
+	let m: [2]u8; m[0] = 9u8; m[1] = 9u8;
+	assert(!( bytes.contains(a[0:4], m[0:2])));
+
+	// Variadic rows. ref/hare/bytes/contains.ha:6.
+	assert(!( bytes.contains(a[0:4])));
+	assert(!(!bytes.contains(a[0:4], n[0:2])));
+	assert(!(!bytes.contains(a[0:4], 7u8)));
+	assert(!(!bytes.contains(a[0:4], m[0:2], n[0:2], 42u8)));
+	assert(!( bytes.contains(a[0:4], m[0:2], 42u8, m[0:2])));
+};
+
+// ref/hare/bytes/contains.ha:25.
+
+@test fn hasprefix_cases() void = {
+	let z: [1]u8;
+	assert(!(!bytes.hasprefix(z[0:0], z[0:0])));
+	let one: [1]u8; one[0] = 0u8;
+	assert(!(!bytes.hasprefix(one[0:1], z[0:0])));
+	assert(!( bytes.hasprefix(z[0:0], one[0:1])));
+	let a: [3]u8; a[0] = 1u8; a[1] = 2u8; a[2] = 3u8;
+	let p12: [2]u8; p12[0] = 1u8; p12[1] = 2u8;
+	assert(!(!bytes.hasprefix(a[0:3], p12[0:2])));
+	let p11: [2]u8; p11[0] = 1u8; p11[1] = 1u8;
+	assert(!( bytes.hasprefix(a[0:3], p11[0:2])));
+	let pl: [4]u8; pl[0] = 1u8; pl[1] = 2u8; pl[2] = 3u8; pl[3] = 4u8;
+	assert(!( bytes.hasprefix(a[0:3], pl[0:4])));
+};
+
+// ref/hare/bytes/contains.ha:40.
+
+@test fn hassuffix_cases() void = {
+	let z: [1]u8;
+	assert(!(!bytes.hassuffix(z[0:0], z[0:0])));
+	let one: [1]u8; one[0] = 0u8;
+	assert(!(!bytes.hassuffix(one[0:1], z[0:0])));
+	assert(!( bytes.hassuffix(z[0:0], one[0:1])));
+	let a: [3]u8; a[0] = 1u8; a[1] = 2u8; a[2] = 3u8;
+	let s23: [2]u8; s23[0] = 2u8; s23[1] = 3u8;
+	assert(!(!bytes.hassuffix(a[0:3], s23[0:2])));
+	let s22: [2]u8; s22[0] = 2u8; s22[1] = 2u8;
+	assert(!( bytes.hassuffix(a[0:3], s22[0:2])));
+	let a4: [4]u8; a4[0] = 1u8; a4[1] = 2u8; a4[2] = 3u8; a4[3] = 4u8;
+	let s234: [3]u8; s234[0] = 2u8; s234[1] = 3u8; s234[2] = 4u8;
+	assert(!(!bytes.hassuffix(a4[0:4], s234[0:3])));
+};