Specify the base URI for bug reports.
The base URI is used to construct bug report messages for
g_test_bug() is called.
Calling this function outside of a test case sets the
default base URI for all test cases. Calling it from within
a test case changes the base URI for the scope of the test
Bug URIs are constructed by appending a bug specific URI
uri_pattern, or by replacing the special string
uri_pattern if that is present.
g_test_bug_base() is not called, bug URIs are formed solely
from the value provided by g_test_bug().