Fix some errors find by Address Sanitizer

[foxtran]

Description
AddressSanitizer detected some errors which I've fixed here:

• mpp_domain_misc: mpp_send is non-blocking operation so, send_buffer must be alive at least until sync point. (Closes mpp_check_field_2d_type1 has use after free #1803)
• mpp_utils_mpi: in-place writing may give errors (not sure that it really happens here, but anyway)
• test_diag_update_buffeer: -fdefault-real-8 generates 1.0e-5 as real(8). Then, real(8) constructor of missvalue is called while it is real(4). So, 4 extra bytes were written. (Closes test_diag_update_manager: wrong datatype is set with -fdefault-real-8 #1805)
• test_xgrid: put_to_xgrid kept address of local/temporary variables generated by array + x expressions. Now, lifetimes of array + x arrays are expanded. That is why after Remove cray pointers from exchange/xgrid.f90 #1778 there is a lot failures of CI. (Closes test_xgrid keeps local temporaries (use after free) #1804)

How Has This Been Tested?
Tested in CI with AddressSanitizer. Unfortunately, not all Address Sanitizer errors are fixed.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules
• New check tests, if applicable, are included
• make distcheck passes

[uramirez8707]

Thank you for fixing these.

[thomas-robinson]

@foxtran Can you open an issue that describes what you are fixing and why and link it to this PR. It helps us with tracking.

Also, just out of curiosity, do you have a use case for FMS that we don't know about. We are interested to hear how you are using FMS.

[foxtran]

We are interested to hear how you are using FMS

I'm playing with flang frontend :-)

[foxtran]

@thomas-robinson, I filed 2 of 4 bugs. Ping me, please, tomorrow, if I will not put other 2 until tomorrow.

[foxtran]

@uramirez8707, can it be merged?

[foxtran]

@rem1776, could you please have a look on it?

[foxtran]

@rem1776, @uramirez8707, any chance that it will be merged? :D

[rem1776]

@bensonr Could you take a look at this when you get a chance?

[bensonr]

My apologies. While I performed the review shortly after the PR was entered, I see I never formally submitted it. Please see my comment regarding the chosen missing value.

[bensonr]

I know you aren't the original author here, but I see a deeper problem with the chosen assignment value. At line 150, there is the possibility for missvalue to be typed as an i8 and associated with an i8 pointer leading to an invalid value.

[foxtran]

As I understood, missvalue can be both real(4) or integer(8). So, this assignment can change type of missvalue that invalidates missval_i8_ptr, defined at line 150, although data still be accessible via missval_i8_ptr.

[foxtran]

There is a shorter example how does it work: https://godbolt.org/z/5jW4P9oY4