patch 9.1.0848: if_lua: v:false/v:true are not evaluated to boolean

Problem:  if_lua: v:false/v:true are not evaluated to boolean
Solution: Use lua_pushboolean() instead of lua_pushinteger().
          (zeertzjq)

fixes: #15994
closes: #11419

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_python3.vim b/src/testdir/test_python3.vim
index 5e2b555..20f9dc6 100644
--- a/src/testdir/test_python3.vim
+++ b/src/testdir/test_python3.vim
@@ -299,7 +299,7 @@
 endfunc
 
 " Test vim.eval() with various types.
-func Test_python3_vim_val()
+func Test_python3_vim_eval()
   call assert_equal("\n8",             execute('py3 print(vim.eval("3+5"))'))
   call assert_equal("\n3.140000",    execute('py3 print(vim.eval("1.01+2.13"))'))
   call assert_equal("\n0.000000",    execute('py3 print(vim.eval("0.0/(1.0/0.0)"))'))