Ignore all debuginfo tests for LLDB that we do not run in CI

We only run LLDB 1500 in CI. Any test with a min-lldb-version above that
is currently ignored. It's not clear any of these tests actually work
with that LLDB version, and they definitely don't work on LLDB ~2100.
So, ignore them until we fix debuginfo testing.

tests/debuginfo/function-arg-initialization.rs

@@ -5,7 +5,8 @@
 // arguments have been properly loaded when setting the breakpoint via the
 // function name.
 
-//@ min-lldb-version: 1800
+// LLDB 1800+ tests were not tested in CI, broke, and now are disabled
+//@ ignore-lldb
 //@ compile-flags:-g
 //@ disable-gdb-pretty-printers
 //@ ignore-backends: gcc