test: fork-per-test runtime

Each @test forks into its own process group with a nonblocking control
pipe carrying framed ready/complete/skip/expect-abort records; timeouts
escalate SIGTERM then SIGKILL over the group. New exports skip,
expectabort, current; new flags -list, -timeout-ms=, -package=. A clean
exit without a completion frame is a harness error, and the exit code
is 0/1 with a discovered/selected/started/completed accounting line.
toktest drops its fixed /tmp path for temp.named so parallel invocations
cannot collide.

lib/ww/syntax/toktest.ww

@@ -23,6 +23,7 @@ package main;
 
 import os;
 import syntax;
+import temp;
 
 
 fn checkname(k: tkind, want: str) void = {
@@ -228,8 +229,12 @@ fn checkprint(fd: i32, t: *tok, want: str) void = {
 // every fputq escape: \\ " \n \t \r, a c<0x20 byte (0x01), c==0x7f,
 // and a printable ('A'). `want` spells the exact emitted line.
 @test fn tokprint_cases() void = {
-	let flags: os.flag = os.flag.RDWR | os.flag.CREATE | os.flag.TRUNC;
-	let fd: i32 = os.open("/tmp/ww_s9_tok.tmp", flags, 384i32);
+	let fd: i32 = 0;
+	let path: str;
+	match (temp.named(&fd, &path, "/tmp", temp.mode.RDWR, 384i32)) {
+	case void => {};
+	case let e: os.oserror => abort();
+	};
 	assert(!(fd < 0));
 
 	let t: tok;
@@ -262,7 +267,7 @@ fn checkprint(fd: i32, t: *tok, want: str) void = {
 	checkprint(fd, &t, "t:1:1 <none>\n");
 
 	assert(!(os.close(fd) != 0));
-	assert(!(os.remove("/tmp/ww_s9_tok.tmp") != 0));
+	assert(!(os.remove(path) != 0));
 };
 
 fn checkfloat(src: str, want: u64) void = {