Revert "params: core, core/vm, miner: 64bit gas instructions (#3514)"

This reverts commit 8b57c49490.

core/vm/int_pool_verifier.go

@@ -1,15 +0,0 @@
-// +build VERIFY_EVM_INTEGER_POOL
-
-package vm
-
-import "fmt"
-
-const verifyPool = true
-
-func verifyIntegerPool(ip *intPool) {
-	for i, item := range ip.pool.data {
-		if item.Cmp(checkVal) != 0 {
-			panic(fmt.Sprintf("%d'th item failed aggressive pool check. Value was modified", i))
-		}
-	}
-}