patch 8.2.3211: Vim9: argument types are not checked at compile time

Problem:    Vim9: argument types are not checked at compile time.
Solution:   Add several more type checks. Fix type check for matchaddpos().
            (Yegappan Lakshmanan, closes #8619)
diff --git a/src/job.c b/src/job.c
index ac35fd1..1f90244 100644
--- a/src/job.c
+++ b/src/job.c
@@ -1658,6 +1658,10 @@
 
     if (check_secure())
 	return;
+
+    if (in_vim9script() && check_for_buffer_arg(argvars, 0) == FAIL)
+	return;
+
     buf = tv_get_buf(&argvars[0], FALSE);
     if (buf == NULL)
 	return;
@@ -1681,6 +1685,10 @@
 
     if (check_secure())
 	return;
+
+    if (in_vim9script() && check_for_buffer_arg(argvars, 0) == FAIL)
+	return;
+
     buf = tv_get_buf(&argvars[0], FALSE);
     if (buf == NULL)
 	return;