Revert "[build] Simplify snapshot target"

This reverts commit f616b372.

Reason for revert: Might break incremental build: https://crbug.com/v8/9966

Original change's description:
> [build] Simplify snapshot target
> 
> Drops unnecessary visibility exception and uses minimum deps required
> for snapshot target.
> 
> Change-Id: I4098a443e9df31c25551540a0b6edfe9500f7bcd
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1910943
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Commit-Queue: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#64907}

TBR=machenbach@chromium.org,jgruber@chromium.org

Change-Id: I01b087406e913faca42e21572d2fb62116c8c222
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:9966
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1912219Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64919}

BUILD.gn

@@ -1387,7 +1387,7 @@ action("v8_dump_build_config") {
 v8_source_set("v8_snapshot") {
   visibility = [ ":*" ]  # Targets in this file can depend on this.
 
-  deps = [ ":v8_maybe_icu" ]
+  deps = []
   public_deps = [
     # This should be public so downstream targets can declare the snapshot
     # output file as their inputs.
@@ -1408,6 +1408,8 @@ v8_source_set("v8_snapshot") {
   configs = [ ":internal_config" ]
 
   if (v8_use_external_startup_data) {
+    deps += [ ":v8_base" ]
+
     sources += [ "src/snapshot/snapshot-external.cc" ]
 
     if (v8_use_multi_snapshots) {
@@ -1420,6 +1422,11 @@ v8_source_set("v8_snapshot") {
       }
     }
   } else {
+    # Also top-level visibility targets can depend on this.
+    visibility += [ "//:gn_visibility" ]
+
+    public_deps += [ ":v8_maybe_icu" ]
+
     sources += [ "$target_gen_dir/snapshot.cc" ]
   }
 }