IBM-supplied default for MSGFLDxx

If message flood automation is enabled by either:

Specifying MSGFLD=(NONE,(ON)) on a CONSOLxx INIT statement, or
Issuing a SETMF ON command before a MSGFLDxx parmlib member has been read using a SET MSGFLD=xx command,

the following built-in defaults are used :

REGULAR parameters:

REGULAR MSGTHRESH=50
REGULAR JOBTHRESH=20
REGULAR INTVLTIME=1
REGULAR SYSIMTIME=2
REGULAR JOBIMTIME=2

REGULAR actions: LOG, AUTO, NODISPLAY, NOCMD

ACTION parameters:

ACTION MSGTHRESH=50
ACTION JOBTHRESH=20
ACTION INTVLTIME=1
ACTION SYSIMTIME=2
ACTION JOBIMTIME=2

ACTION actions: LOG, AUTO, NODISPLAY, NOCMD, NORETAIN

SPECIFIC parameters:

SPECIFIC MSGTHRESH=50
SPECIFIC MSGLIMIT=20
SPECIFIC INTVLTIME=1
SPECIFIC SYSIMTIME=2
SPECIFIC MSGIMTIME=2

SPECIFIC actions:LOG, AUTO, NODISPLAY, NORETAIN,NOIGNORE

SPECIFIC message set:
```
IOS000I NOLOG,NOAUTO,NODISPLAY
IOS002A NOLOG,NOAUTO,NODISPLAY
IOS017I NOLOG,NOAUTO,NODISPLAY
IOS107I NOLOG,NOAUTO,NODISPLAY
IOS109E NOLOG,NOAUTO,NODISPLAY
IOS251I NOLOG,NOAUTO,NODISPLAY
IOS291I NOLOG,NOAUTO,NODISPLAY
IOS444I NOLOG,NOAUTO,NODISPLAY
IOS450E NOLOG,NOAUTO,NODISPLAY
IEA476E NOLOG,NOAUTO,NODISPLAY
IEA491E NOLOG,NOAUTO,NODISPLAY
IEA494I NOLOG,NOAUTO,NODISPLAY
IEA497I NOLOG,NOAUTO,NODISPLAY
```
This message set was chosen to handle message floods that can occur during the GDPS® HyperSwap® IPL processing. Note that the IEA497I message has continuation messages that are issued as separate single line messages, without message IDs. These separate messages are not handled.

When a MSGFLDxx parmlib member is read, message flood automation first replaces any parameters that it was using with the built-in default values. It then replaces those values with any values specified in the parmlib member. This ensures that message flood automation always has valid policy values that it can use. The exception to this are the built-in SPECIFIC messages which are automatically deleted by the first MSGFLDxx PARMLIB member read.