fix: remove wrong assert in Synth PoRep code path

Due to me understanding the code wrongly during the refactoring at
#1720, there
was a wrong assert inserted into the code. With removing this assert
the lifecycle 32GiB test as well as the benchy synthetic proofs
generation works as expected again.

This commit also updates the README with the correct command to run
benchy for synthetic proofs generation.

README.md

@@ -132,7 +132,7 @@ The main benchmarking tool is called `benchy`.  `benchy` has several subcommands
 > cargo run --release --bin benchy -- window-post-fake --size 2KiB --fake
 > cargo run --release --bin benchy -- prodbench
 # After a preserved cache is generated, this command tests *only* synthetic proof generation
-> cargo run --release --bin benchy -- porep --size 2KiB --synthetic --cache /d1/nemo/tmp/cache-2k --skip-precommit-phase1 --skip-precommit-phase2 --skip-commit-phase1 --skip-commit-phase2
+> cargo run --release --bin benchy -- porep --size 2KiB -api-features=synthetic-porep --cache /d1/nemo/tmp/cache-2k --skip-precommit-phase1 --skip-precommit-phase2 --skip-commit-phase1 --skip-commit-phase2
 ```
 
 ### Window PoSt Bench usages

storage-proofs-porep/src/stacked/vanilla/proof.rs

@@ -141,7 +141,6 @@ impl<'a, Tree: 'static + MerkleTreeTrait, G: 'static + Hasher> StackedDrg<'a, Tr
                 // If there are no synthetic vanilla proofs stored on disk yet, generate them.
                 if pub_inputs.seed.is_none() {
                     info!("generating synthetic vanilla proofs in a single partition");
-                    assert_eq!(partition_count, 1);
 
                     let comm_r = pub_inputs.tau.as_ref().expect("tau is set").comm_r;
                     // Derive the set of challenges we are proving over.