Remove extraneous console output from TransactionStateManager tests

[whymarrh]

This PR removes the single use of console.log from the TransactionStateManager tests to reduce noise in the output.

Before:

$ yarn test:unit
yarn run v1.19.2
$ cross-env METAMASK_ENV=test mocha --exit --require test/setup.js --recursive "test/unit/**/*.js" "ui/app/**/*.test.js"


  TransactionStateManager
    #setTxStatusSigned
      ✓ sets the tx status to signed
      ✓ should emit a signed event to signal the exciton of callback
    #setTxStatusRejected
      ✓ sets the tx status to rejected and removes it from history
Error:  1
      ✓ should emit a rejected event to signal the exciton of callback
    #getFullTxList
      ✓ when new should return empty array
    #getTxList
      ✓ when new should return empty array
    #addTx
      ✓ adds a tx returned in getTxList
      ✓ throws error and does not add tx if txParams are invalid
      ✓ does not override txs from other networks
      ✓ cuts off early txs beyond a limit
      ✓ cuts off early txs beyond a limit whether or not it is confirmed or rejected
      ✓ cuts off early txs beyond a limit but does not cut unapproved txs
    #updateTx
      ✓ replaces the tx with the same id
      ✓ throws error and does not update tx if txParams are invalid
      ✓ updates gas price and adds history items
    #getUnapprovedTxList
      ✓ returns unapproved txs in a hash
    #getTx
      ✓ returns a tx with the requested id
    #getFilteredTxList
      ✓ returns a tx with the requested data
    #wipeTransactions
      ✓ should remove only the transactions from a specific address
      ✓ should not remove the transactions from other networks
    #_removeTx
      ✓ should remove the transaction from the storage
      ✓ should only remove the transaction with ID 1 from the storage


  22 passing (306ms)

✨  Done in 16.27s.

After:

$ yarn test:unit
yarn run v1.19.2
$ cross-env METAMASK_ENV=test mocha --exit --require test/setup.js --recursive "test/unit/**/*.js" "ui/app/**/*.test.js"


  TransactionStateManager
    #setTxStatusSigned
      ✓ sets the tx status to signed
      ✓ should emit a signed event to signal the exciton of callback
    #setTxStatusRejected
      ✓ sets the tx status to rejected and removes it from history
      ✓ should emit a rejected event to signal the exciton of callback
    #getFullTxList
      ✓ when new should return empty array
    #getTxList
      ✓ when new should return empty array
    #addTx
      ✓ adds a tx returned in getTxList
      ✓ throws error and does not add tx if txParams are invalid
      ✓ does not override txs from other networks
      ✓ cuts off early txs beyond a limit
      ✓ cuts off early txs beyond a limit whether or not it is confirmed or rejected
      ✓ cuts off early txs beyond a limit but does not cut unapproved txs
    #updateTx
      ✓ replaces the tx with the same id
      ✓ throws error and does not update tx if txParams are invalid
      ✓ updates gas price and adds history items
    #getUnapprovedTxList
      ✓ returns unapproved txs in a hash
    #getTx
      ✓ returns a tx with the requested id
    #getFilteredTxList
      ✓ returns a tx with the requested data
    #wipeTransactions
      ✓ should remove only the transactions from a specific address
      ✓ should not remove the transactions from other networks
    #_removeTx
      ✓ should remove the transaction from the storage
      ✓ should only remove the transaction with ID 1 from the storage


  22 passing (326ms)

✨  Done in 17.53s.

[Gudahtt]

Thanks, LGTM!

The build failure is unrelated; just needs to be re-run I'm guessing.