Snapshots: remove "runtime/" snapshot

[bartlomieju]

Following issues need to be addressed first:

• Snapshots: move some of the bootstrap options from runtime to snapshot time #21133
• Snapshots: factor out generation of "runtime/" snapshot to a helper module #21134
• Snapshots: move "op_npm_process_state" to "ext/node" #21135
• Snapshots: remove cli/js/40_testing.js and cli/js/40_jupyter.js from the snapshot #21136

Once we do all of them, we can start to remove snapshot creating in the "runtime/" crate. This will involve several stages:

• remove usage of the snapshot in "runtime/js.rs" - this is already gated behind a cargo feature called dont_create_runtime_snapshot:
  https://github.com/denoland/deno/blob/9010b8df53cd37f0410e08c43a194667974686a2/runtime/js.rs#L5C19-L19
  This cargo feature is already clunky to use - we don't specify it for deno_runtime build dependency in "cli":
  

  deno/cli/Cargo.toml

  Lines 34 to 35 in 9010b8d

  	[build-dependencies]
  	deno_runtime = { workspace = true, features = ["exclude_runtime_main_js", "include_js_files_for_snapshotting"] }

  
  but specify it for regular dependency:
  

  deno/cli/Cargo.toml

  Line 58 in 9010b8d

  deno_runtime = { workspace = true, features = ["dont_create_runtime_snapshot", "exclude_runtime_main_js", "include_js_files_for_snapshotting"] }

  
  Lots of complexity for little gain...
• remove usage of said snapshot in "runtime/worker.rs" and "runtime/web_worker.rs" - the snapshot is used as a fallback if user doesn't provide snapshot of their own:
  

  deno/runtime/worker.rs

  Lines 352 to 354 in 9010b8d

  	startup_snapshot: options
  	.startup_snapshot
  	.or_else(crate::js::deno_isolate_init),

  
  This is really only used by the embedders of the "deno_runtime" crate (we don't use it in CLI anyway). We can handle this better by defaulting to not using a snapshot and instead embedding the source files in the binary (similarly to what happens if "__runtime_js_source" cargo feature is used). With Snapshots: factor out generation of "runtime/" snapshot to a helper module #21134 it should be very easy for embedders to create a snapshot and integrate it into their own build script

Special care needs to be taken to account for include_js_files_for_snapshotting cargo feature used both in deno_core and deno_runtime.

I expect this effort to happen over several PRs.