Bring Lua to 5.4.6. (#1214)

This essentially re-does the work of #875 on top of master.

This is what I did to check that Cosmo's Lua extensions still worked:

```
$ build/bootstrap/make MODE=aarch64 o/aarch64/third_party/lua/lua
$ ape o/aarch64/third_party/lua/lua
>: 10
10
>: 010
8
>: 0b10
2
>: string.byte("\e")
27
>: "Hello, %s" % {"world"}
Hello, world
>: "*" * 3
***
```

`luaL_traceback2` was used to show the stack trace with parameter
values; it's used in `LuaCallWithTrace`, which is used in Redbean to run
Lua code. You should be able to see the extended stack trace by running
something like this: `redbean -e "function a(b)c()end a(2)"` (with
"params" indicating the extended stack trace):

```
stack traceback:
 [string "function a(b)c()end a(2)"]:1: in function 'a', params: b = 2;
 [string "function a(b)c()end a(2)"]:1: in main chunk
```
@pkulchenko confirmed that I get the expected result with the updated
code.

This is what I did to check that Lua itself still worked:

```
$ cd third_party/lua/test/
$ ape ../../../o/aarch64/third_party/lua/lua all.lua
```

There's one test failure, in `files.lua`:

```
***** FILE 'files.lua'*****
testing i/o
../../../o/aarch64/third_party/lua/lua: files.lua:84: assertion failed!
stack traceback:
[C]: in function 'assert'
files.lua:84: in main chunk
(...tail calls...)
all.lua:195: in main chunk
[C]: in ?
.>>> closing state <<<
```

That isn't a result of these changes; the same test is failing in
master.

The failure is here:

```lua
if not _port then   -- invalid seek
  local status, msg, code = io.stdin:seek("set", 1000)
  assert(not status and type(msg) == "string" and type(code) == "number")
end
```

The test expects a seek to offset 1,000 on stdin to fail — but it
doesn't. `status` ends up being the new offset rather than `nil`.

If I comment out that one test, the remaining tests succeed.

third_party/lua/test/cstack.lua

@@ -84,6 +84,32 @@ do   -- bug in 5.4.0
 end
 
 
+do    -- bug since 5.4.0
+  local count = 0
+  print("chain of 'coroutine.close'")
+  -- create N coroutines forming a list so that each one, when closed,
+  -- closes the previous one. (With a large enough N, previous Lua
+  -- versions crash in this test.)
+  local coro = false
+  for i = 1, 1000 do
+    local previous = coro
+    coro = coroutine.create(function()
+      local cc <close> = setmetatable({}, {__close=function()
+        count = count + 1
+        if previous then
+          assert(coroutine.close(previous))
+        end
+      end})
+      coroutine.yield()   -- leaves 'cc' pending to be closed
+    end)
+    assert(coroutine.resume(coro))  -- start it and run until it yields
+  end
+  local st, msg = coroutine.close(coro)
+  assert(not st and string.find(msg, "C stack overflow"))
+  print("final count: ", count)
+end
+
+
 do
   print("nesting of resuming yielded coroutines")
   local count = 0
@@ -103,6 +129,20 @@ do
 end
 
 
+do    -- bug in 5.4.2
+  print("nesting coroutines running after recoverable errors")
+  local count = 0
+  local function foo()
+    count = count + 1
+    pcall(1)   -- create an error
+    -- running now inside 'precover' ("protected recover")
+    coroutine.wrap(foo)()   -- call another coroutine
+  end
+  checkerror("C stack overflow", foo)
+  print("final count: ", count)
+end
+
+
 if T then
   print("testing stack recovery")
   local N = 0      -- trace number of calls