Refactor x2sys_cross to remove verbose info and return output statements

[weiji14]

Description of proposed changes

Silences captured stderr messages in the log from running x2sys_cross. Patches #546.

___________________ test_x2sys_cross_input_file_output_file ____________________
----------------------------- Captured stderr call -----------------------------
x2sys_cross [INFORMATION]: Files found: 1
x2sys_cross [INFORMATION]: Checking for duplicates :
x2sys_cross [INFORMATION]: 0 found
Warning: ss [WARNING]: No time column, use dummy times
Not a valid unit: c [meter assumed]
Not a valid unit: c [meter assumed]
x2sys_cross [INFORMATION]: Writing Data Table to file /home/runner/work/pygmt/pygmt/tmp-test-dir-with-unique-name/X2SYSr58ly6wo/tmp_coe.txt
x2sys_cross [INFORMATION]: Processing @tut_ship - @tut_ship : 14294
_________________ test_x2sys_cross_input_file_output_dataframe _________________
----------------------------- Captured stderr call -----------------------------
x2sys_cross [INFORMATION]: Files found: 1
x2sys_cross [INFORMATION]: Checking for duplicates :
x2sys_cross [INFORMATION]: 0 found
Warning: ss [WARNING]: No time column, use dummy times
Not a valid unit: c [meter assumed]
Not a valid unit: c [meter assumed]
x2sys_cross [INFORMATION]: Writing Data Table to file /tmp/pygmt-hmkwjhzz.txt
x2sys_cross [INFORMATION]: Processing @tut_ship - @tut_ship : 14294
______________ test_x2sys_cross_input_dataframe_output_dataframe _______________
----------------------------- Captured stderr call -----------------------------
x2sys_cross [INFORMATION]: Files found: 1
x2sys_cross [INFORMATION]: Checking for duplicates :
x2sys_cross [INFORMATION]: 0 found
Warning: ss [WARNING]: No time column, use dummy times
Not a valid unit: c [meter assumed]
Not a valid unit: c [meter assumed]
x2sys_cross [INFORMATION]: Writing Data Table to file /tmp/pygmt-1o71k5fm.txt
x2sys_cross [INFORMATION]: Processing track-c48ce7c - track-c48ce7c : 14
____________________ test_x2sys_cross_input_two_dataframes _____________________
----------------------------- Captured stderr call -----------------------------
x2sys_cross [INFORMATION]: Files found: 2
x2sys_cross [INFORMATION]: Checking for duplicates :
x2sys_cross [INFORMATION]: 0 found
x2sys_cross [INFORMATION]: Writing Data Table to file /tmp/pygmt-twq1zmqn.txt
x2sys_cross [INFORMATION]: Processing track-ab8038e - track-ce196c4 : 30
__________________ test_x2sys_cross_input_dataframe_with_nan ___________________
----------------------------- Captured stderr call -----------------------------
Warning: ss [WARNING]: No time column, use dummy times
_____________________ test_x2sys_cross_input_two_filenames _____________________
----------------------------- Captured stderr call -----------------------------
x2sys_cross [INFORMATION]: Files found: 2
x2sys_cross [INFORMATION]: Checking for duplicates :
x2sys_cross [INFORMATION]: 0 found
Warning: ss [WARNING]: No time column, use dummy times
Not a valid unit: c [meter assumed]
Not a valid unit: c [meter assumed]
x2sys_cross [INFORMATION]: Writing Data Table to file /tmp/pygmt-qlquqjz8.txt
x2sys_cross [INFORMATION]: Processing track_0 - track_1 : 24
_______________ test_x2sys_cross_region_interpolation_numpoints ________________
----------------------------- Captured stderr call -----------------------------
Warning: ss [WARNING]: No time column, use dummy times
Not a valid unit: c [meter assumed]
Not a valid unit: c [meter assumed]
_________________________ test_x2sys_cross_trackvalues _________________________
----------------------------- Captured stderr call -----------------------------
Warning: ss [WARNING]: No time column, use dummy times
Not a valid unit: c [meter assumed]
Not a valid unit: c [meter assumed]

Fixes #

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If adding new functionality, add an example to docstrings or tutorials.

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