some code improvements:

[lispc]

1. allow read degree from env var （we may bring in aggregation circuit soon, so more flexible degree needed)
2. better naming for some proving related vars
3. check of params file length when loading

[0xmountaintop]

failures:

---- test_state_evm_connect stdout ----
thread 'test_state_evm_connect' panicked at 'assertion failed: `(left == right)`
  left: `(0x1b5a312208e0c9a2b0926efb28e88fbd82b477909d79ec2c4d9518f92e5c4d0d, 0x03960a37fa44bf384bd71641a275fad16521769b004e080e80907015fc57383d)`,
 right: `(0x0d45135f3041354bcc97cd3c456a8420e6583ea2be3273a47662a423720a1c6c, 0x03cd2df961cab95ca4915e63f8b2d9a3468f4ebbbc51293a4c243bbf036ce8fd)`', zkevm/tests/integration.rs:160:5
stack backtrace:
   0: rust_begin_unwind
             at /rustc/d914f17ca71a33a89b2dc3436fca51b1a091559e/library/std/src/panicking.rs:498:5
   1: core::panicking::panic_fmt
             at /rustc/d914f17ca71a33a89b2dc3436fca51b1a091559e/library/core/src/panicking.rs:106:14
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed
   4: core::ops::function::FnOnce::call_once
   5: core::ops::function::FnOnce::call_once
             at /rustc/d914f17ca71a33a89b2dc3436fca51b1a091559e/library/core/src/ops/function.rs:227:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.


failures:
    test_state_evm_connect

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 2 filtered out; finished in 700.73s