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/closure.lua

@@ -4,7 +4,7 @@
 print "testing closures"
 
 local A,B = 0,{g=10}
-function f(x)
+local function f(x)
   local a = {}
   for i=1,1000 do
     local y = 0
@@ -89,6 +89,7 @@ assert(r == "a" and s == "b")
 
 
 -- testing closures with 'for' control variable x break
+local f
 for i=1,3 do
   f = function () return i end
   break
@@ -139,7 +140,7 @@ assert(b('get') == 'xuxu')
 b('set', 10); assert(b('get') == 14)
 
 
-local w
+local y, w
 -- testing multi-level closure
 function f(x)
   return function (y)
@@ -230,6 +231,7 @@ t()
 -- test for debug manipulation of upvalues
 local debug = require'debug'
 
+local foo1, foo2, foo3
 do
   local a , b, c = 3, 5, 7
   foo1 = function () return a+b end;