cmd/utils, eth/ethconfig: change default cache settings (#33975)

This PR fixes a regression introduced in https://github.com/ethereum/go-ethereum/pull/33836/changes

Before PR 33836, running mainnet would automatically bump the cache size
to 4GB and trigger a cache re-calculation, specifically setting the key-value 
database cache to 2GB.
 
After PR 33836, this logic was removed, and the cache value is no longer
recomputed if no command line flags are specified. The default key-value 
database cache is 512MB.

This PR bumps the default key-value database cache size alongside the
default cache size for other components (such as snapshot) accordingly.

cmd/utils/flags.go

@@ -218,17 +218,11 @@ var (
 		Usage: "Max number of elements (0 = no limit)",
 		Value: 0,
 	}
-	TopFlag = &cli.IntFlag{
-		Name:  "top",
-		Usage: "Print the top N results",
-		Value: 5,
-	}
 	OutputFileFlag = &cli.StringFlag{
 		Name:  "output",
 		Usage: "Writes the result in json to the output",
 		Value: "",
 	}
-
 	SnapshotFlag = &cli.BoolFlag{
 		Name:     "snapshot",
 		Usage:    `Enables snapshot-database mode (default = enable)`,
@@ -490,7 +484,7 @@ var (
 	// Performance tuning settings
 	CacheFlag = &cli.IntFlag{
 		Name:     "cache",
-		Usage:    "Megabytes of memory allocated to internal caching (default = 4096 mainnet full node, 128 light mode)",
+		Usage:    "Megabytes of memory allocated to internal caching",
 		Value:    4096,
 		Category: flags.PerfCategory,
 	}

eth/ethconfig/config.go

@@ -59,11 +59,11 @@ var Defaults = Config{
 	StateHistory:            pathdb.Defaults.StateHistory,
 	TrienodeHistory:         pathdb.Defaults.TrienodeHistory,
 	NodeFullValueCheckpoint: pathdb.Defaults.FullValueCheckpoint,
-	DatabaseCache:           512,
-	TrieCleanCache:          154,
-	TrieDirtyCache:          256,
+	DatabaseCache:           2048,
+	TrieCleanCache:          614,
+	TrieDirtyCache:          1024,
+	SnapshotCache:           409,
 	TrieTimeout:             60 * time.Minute,
-	SnapshotCache:           102,
 	FilterLogCacheSize:      32,
 	LogQueryLimit:           1000,
 	Miner:                   miner.DefaultConfig,