A number of small script fixes/tweaks from usage

- Fixed prettyasserts.py parsing when '->' is in expr

- Made prettyasserts.py failures not crash (yay dynamic typing)

- Fixed the initial state of the emubd disk file to match the internal
  state in RAM

- Fixed true/false getting changed to True/False in test.py/bench.py
  defines

- Fixed accidental substring matching in plot.py's --by comparison

- Fixed a missed LFS_BLOCk_CYCLES in test_superblocks.toml that was
  missed

- Changed test.py/bench.py -v to only show commands being run

  Including the test output is still possible with test.py -v -O-, making
  the implicit inclusion redundant and noisy.

- Added license comments to bench_runner/test_runner

bd/lfs_emubd.c

@@ -164,6 +164,19 @@ int lfs_emubd_createcfg(const struct lfs_config *cfg, const char *path,
             memset(bd->disk->scratch,
                     bd->cfg->erase_value,
                     cfg->block_size);
+
+            // go ahead and erase all of the disk, otherwise the file will not
+            // match our internal representation
+            for (size_t i = 0; i < cfg->block_count; i++) {
+                ssize_t res = write(bd->disk->fd,
+                        bd->disk->scratch,
+                        cfg->block_size);
+                if (res < 0) {
+                    int err = -errno;
+                    LFS_EMUBD_TRACE("lfs_emubd_create -> %d", err);
+                    return err;
+                }
+            }
         }
     }