Initializing nag tests to NaN indicates there are issues which need to be addressed

### What happened?

When `-nan` is added to the compilation flags for NAG runs, the following tests fail. There may be one or more bugs that need to be solved.

FAIL ERC_D_Ln9_Vnuopc.f10_f10_mg37.QPC5.izumi_nag.cam-carma_sea_salt RUN time=60
FAIL ERC_D_Ln9_Vnuopc.f10_f10_mg37.QPC6.izumi_nag.cam-outfrq3s_am RUN time=202
FAIL ERC_D_Ln9_Vnuopc.f10_f10_mg37.QPC6.izumi_nag.cam-outfrq3s_convmic RUN time=248
FAIL ERC_D_Ln9_Vnuopc.f10_f10_mg37.QPC6.izumi_nag.cam-outfrq3s_cospsathist RUN time=242
FAIL ERC_D_Ln9_Vnuopc.f10_f10_mg37.QPC6.izumi_nag.cam-outfrq3s RUN time=247
FAIL ERC_D_Ln9_Vnuopc.f10_f10_mg37.QPWmaC6.izumi_nag.cam-outfrq3s RUN time=267
FAIL ERC_D_Ln9_Vnuopc.mpasa480z32_mpasa480.FHS94.izumi_nag.cam-outfrq3s_usecase RUN time=6
FAIL ERI_D_Ln18_Vnuopc.f19_f19_mg17.QPC6.izumi_nag.cam-ghgrmp_e8 RUN time=243
FAIL SMS_D_Ln6_Vnuopc.ne5_ne5_mg37.QPWmaC4.izumi_nag.cam-outfrq3s_physgrid_tem RUN time=54
FAIL SMS_D_Ln9_Vnuopc.f10_f10_mg37.QPC6.izumi_nag.cam-outfrq3s_ba RUN time=178
FAIL SMS_P48x1_D_Ln3_Vnuopc.f09_f09_mg17.QPC6HIST.izumi_nag.cam-outfrq3s_co2cycle_usecase RUN time=209

### What are the steps to reproduce the bug?

Add -nan to the flags as shown below to the file ccs_config/machines/cmake_macros/nag.cmake (until ccs_config has this flag added to it by default).

```
if (DEBUG)
string(APPEND FFLAGS " -nan -C=all -g -time -f2003 -ieee=stop")
endif()
```

### What CAM tag were you using?

cam6_3_100

### What machine were you running CAM on?

CGD machine (e.g. izumi)

### What compiler were you using?

NAG

### Path to a case directory, if applicable

_No response_

### Will you be addressing this bug yourself?

Yes

### Extra info

_No response_