improve ResetTestRootWithChainID() concurrency safety (#3291)

* improve ResetTestRootWithChainID() concurrency safety

Rely on ioutil.TempDir() to create test root directories and ensure
multiple same-chain id test cases can run in parallel.

* Update config/toml.go

Co-Authored-By: alessio <quadrispro@ubuntu.com>

* clean up test directories after completion

Closes: #1034

* Remove redundant EnsureDir call

* s/PanicSafety()/panic()/s

* Put create dir functionality back in ResetTestRootWithChainID

* Place test directories in OS's tempdir

In modern UNIX and UNIX-like systems /tmp is very often
mounted as tmpfs. This might speed test execution a bit.

* Set 0700 to a const

* rootsDirs -> configRootDirs

* Don't double remove directories

* Avoid global variables

* Fix consensus tests

* Reduce defer stack

* Address review comments

* Try to fix tests

* Update CHANGELOG_PENDING.md

Co-Authored-By: alessio <quadrispro@ubuntu.com>

* Update consensus/common_test.go

Co-Authored-By: alessio <quadrispro@ubuntu.com>

* Update consensus/common_test.go

Co-Authored-By: alessio <quadrispro@ubuntu.com>

lite/proxy/query_test.go

@@ -27,13 +27,15 @@ var waitForEventTimeout = 5 * time.Second
 // TODO fix tests!!
 
 func TestMain(m *testing.M) {
+	var cleanup func()
 	app := kvstore.NewKVStoreApplication()
-	node = rpctest.StartTendermint(app)
+	node, cleanup = rpctest.StartTendermint(app)
 
 	code := m.Run()
 
 	node.Stop()
 	node.Wait()
+	cleanup()
 	os.Exit(code)
 }