test(ldgen): added test simulating a .*.c file

tools/ldgen/test/data/test_entity/parse_test.txt

@@ -17,3 +17,10 @@ Sections:
 Idx Name          Size      VMA       LMA       File off  Algn
   0 .literal.ěščřžýáíé 00000018  00000000  00000000  00000034  2**2
                   CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
+
+o_suffix.c.o:     file format elf32-littleriscv
+
+Sections:
+Idx Name          Size      VMA       LMA       File off  Algn
+  0 .find_me         00000000  00000000  00000000  00000034  2**0
+                  CONTENTS, ALLOC, LOAD, READONLY, CODE

tools/ldgen/test/test_entity.py

@@ -236,6 +236,9 @@ class EntityDBTest(unittest.TestCase):
         sections = self.entities.get_sections('ěščřžýáíé.a', 'FreeRTOS-ěščřžýáíé')
         self.assertEqual(set(sections), set(['.literal.ěščřžýáíé']))
 
+        sections = self.entities.get_sections('ěščřžýáíé.a', 'o_suffix')
+        self.assertEqual(set(sections), set(['.find_me']))
+
 
 if __name__ == '__main__':
     unittest.main()