chore(ci): Remove the slowest parallel benchmark (#11187)

**Description:**

This is the slowest benchmark up to 15 minutes. And running a parallel version of the benchmark specifically on Codspeed doesn’t make much sense.

Author: CPunisher

crates/swc_ecma_transforms_base/Cargo.toml

@@ -51,7 +51,3 @@ testing                    = { version = "16.0.0", path = "../testing" }
 [[bench]]
 harness = false
 name    = "base"
-
-[[bench]]
-harness = false
-name    = "parallel"