fix mlog-ing before initialized (#8753)

Dump mlog to STDOUT before initialized, to allow for logging failures
that occur due to config parsing, etc.

Fix file logging to honour logger.FileJson instead of copying the
logger.ConsoleJson setting.

mlog/global.go

@@ -35,8 +35,8 @@ func GloballyEnableDebugLogForTest() {
 	globalLogger.consoleLevel.SetLevel(zapcore.DebugLevel)
 }
 
-var Debug LogFunc
-var Info LogFunc
-var Warn LogFunc
-var Error LogFunc
-var Critical LogFunc
+var Debug LogFunc = defaultDebugLog
+var Info LogFunc = defaultInfoLog
+var Warn LogFunc = defaultWarnLog
+var Error LogFunc = defaultErrorLog
+var Critical LogFunc = defaultCriticalLog