Move the location of the solver test case to /run/agama/testcase

[lslezak]

Problem

• As discussed on the Slack, Agama should not save the solver testcase to /var/log/zypp.
• Related to Automatically save solver testcase #3242

Solution

• Use /run/agama for that

Additional changes

• Do not save the solver testcase when ZYPP_FULLLOG=1 is set, in that case libzypp creates the solver testcase automatically in the /var/log/YaST2/autoTestcase directory. Avoid dumping it twice.

Testing

• Tested manually