fix(lua): relax vim.wait() timeout validation (#36907)

fix(lua): relax `vim.wait()` timeout validation #36900

Problem:
After bc0635a9fc `vim.wait()` rejects floats
and NaN values.

Solution:
Restore the prior behavior, while still supporting `math.huge`. Update
tests to cover float case.

(cherry picked from commit b87bdef2a8)

test/functional/lua/vim_spec.lua

@@ -3636,7 +3636,7 @@ stack traceback:
         true,
         exec_lua [[
         local start_time = vim.uv.hrtime()
-        vim.wait(50, nil)
+        vim.wait(50.1, nil)
         return vim.uv.hrtime() - start_time > 25000
       ]]
       )