work around debuginfo behavior change

Author: RalfJung

tests/debuginfo/macro-stepping.rs

@@ -1,3 +1,8 @@
+//! This tests that `next` skips over macro invocations correctly.
+//! The `#locN` markers have no meaning for compiletest, we include them just
+//! so that the debugger prints them when printing the current source location,
+//! and we can match on them for testing purposes.
+
 //@ ignore-android
 //@ min-lldb-version: 1800
 //@ min-gdb-version: 13.0
@@ -63,6 +68,8 @@ extern crate macro_stepping; // exports new_scope!()
 //@ lldb-command:frame select
 //@ lldb-check:[...] #loc3 [...]
 //@ lldb-command:next
+// FIXME: for some reason we need two `next` to skip over the `vec!`.
+//@ lldb-command:next
 //@ lldb-command:frame select
 //@ lldb-check:[...] #loc4 [...]
 //@ lldb-command:next