twister: Switch to a non-greedy regex

When parsing test names from symbol names, use a non-greedy match to
avoid parsing test names with __ in them.

The symbol looks like z_ztest_unit_test__SUITE__TEST. It is more likely
that a test name will contain __ than a suite name, so now something
z_ztest_unit_test__a_b__c_d__e_f will be parsed as suite:a_b
test:c_d__e_f, whereas it used to be parsed as suite:a_b__c_d test:e_f

Signed-off-by: Jeremy Bettis <jbettis@google.com>

Author: jeremybettis

scripts/pylib/twister/twisterlib/runner.py

@@ -684,7 +684,7 @@ def determine_testcases(self, results):
         elf = ELFFile(open(elf_file, "rb"))
 
         logger.debug(f"Test instance {self.instance.name} already has {len(self.instance.testcases)} cases.")
-        new_ztest_unit_test_regex = re.compile(r"z_ztest_unit_test__([^\s]*)__([^\s]*)")
+        new_ztest_unit_test_regex = re.compile(r"z_ztest_unit_test__([^\s]+?)__([^\s]*)")
         detected_cases = []
         for section in elf.iter_sections():
             if isinstance(section, SymbolTableSection):