OpenVAF crash when compiling

[gjcoram]

The attached Verilog-A module caused OpenVAF to crash and produce the attached log file. Note that this module does have a declared parameter, so it's not the same issue as #103
white_noise_i.va.txt
openvaf-crash-1713217346.log

[gjcoram]

white2.va compiles. Notes:

1. OpenVAF does not like having only a noise contribution -- and you can't fake it out by having a 0 dc contribution I(a,b) <+ 0;
2. OpenVAF does not like having only a single terminal.

white1.va.txt
white2.va.txt
white3.va.txt

[gjcoram]

Debug stack trace:

thread '' panicked at 'called Option::unwrap() on a None value', openvaf/osdi/src/inst_data.rs:902:26
stack backtrace:
0: rust_begin_unwind
at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/panicking.rs:584:5
1: core::panicking::panic_fmt
at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/core/src/panicking.rs:142:14
2: core::panicking::panic
at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/core/src/panicking.rs:48:5
3: core::option::Option::unwrap
at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/core/src/option.rs:775:21
4: osdi::inst_data::::load_eval_output
at ./openvaf/osdi/src/inst_data.rs:900:53
5: osdi::load::::load_noise
at ./openvaf/osdi/src/load.rs:63:27