Unit test for simple structs fails sometimes

[Lana243]

While running tests on Github unit test Server_Test.Simple_Structs sometimes fails. Please see the following attempts:

1. https://github.com/UnitTestBot/UTBotCpp/runs/6449300319?check_suite_focus=true#step:5:1163

[ RUN      ] Server_Test.Simple_Structs
In file included from /__w/UTBotCpp/UTBotCpp/server/test/suites/server/simple_structs.c:5:
/__w/UTBotCpp/UTBotCpp/server/test/suites/server/simple_structs.h:28:9: warning: declaration does not declare anything [-Wmissing-declarations]
        struct InInnerStruct {
        ^
1 warning generated.
In file included from /__w/UTBotCpp/UTBotCpp/server/test/suites/server/simple_structs.c:5:
/__w/UTBotCpp/UTBotCpp/server/test/suites/server/simple_structs.h:28:9: warning: declaration does not declare anything [-Wmissing-declarations]
        struct InInnerStruct {
        ^
1 warning generated.
2022-05-16 09:34:47.078              Server.cpp:283   INFO| KLEE time: 1587 ms

../test/framework/TestUtils.cpp:60: Failure
Expected: (-1) != (ind), actual: -1 vs -1
Predicates don't match test cases:
	Not found test case for predicate at position:0
	Function name: operate_with_inner_structs
	Remaining non-matched test cases:
		Parameters values: {{'a', {0U, 0LL}, 15}, 5, 101LL} 
		Return value: 'a'
		Parameters values: {{'c', {1U, 0LL}, 0}, 0, 0LL} 
		Return value: 'g'
		Parameters values: {{'c', {0U, 4LL}, 0}, 0, 0LL} 
		Return value: 'o'
		Parameters values: {{'c', {0U, 0LL}, 0}, 5, 0LL} 
		Return value: 'e'
		Parameters values: {{'c', {0U, 0LL}, 0}, 5, 101LL} 
		Return value: 'e'
		Parameters values: {{'c', {0U, 0LL}, 0}, 5, 5LL} 
		Return value: 'e'
		Parameters values: {{'c', {0U, 0LL}, 0}, 0, 0LL} 
		Return value: 'e'

[  FAILED  ] Server_Test.Simple_Structs (1983 ms)

2. https://github.com/UnitTestBot/UTBotCpp/runs/6474050621?check_suite_focus=true#step:5:1179

[ RUN      ] Server_Test.Simple_Structs
In file included from /__w/UTBotCpp/UTBotCpp/server/test/suites/server/simple_structs.c:5:
/__w/UTBotCpp/UTBotCpp/server/test/suites/server/simple_structs.h:28:9: warning: declaration does not declare anything [-Wmissing-declarations]
        struct InInnerStruct {
        ^
1 warning generated.
In file included from /__w/UTBotCpp/UTBotCpp/server/test/suites/server/simple_structs.c:5:
/__w/UTBotCpp/UTBotCpp/server/test/suites/server/simple_structs.h:28:9: warning: declaration does not declare anything [-Wmissing-declarations]
        struct InInnerStruct {
        ^
1 warning generated.
2022-05-17 16:03:49.743              Server.cpp:282   INFO| KLEE time: 1747 ms

../test/framework/TestUtils.cpp:37: Failure
Expected: (testCases.size()) >= (predicates.size()), actual: 2 vs 3
 Number of test cases (2) less than number of predicates (3) for function get_sign_struct.
../test/framework/TestUtils.cpp:60: Failure
Expected: (-1) != (ind), actual: -1 vs -1
Predicates don't match test cases:
	Not found test case for predicate at position:2
	Function name: get_sign_struct
	Remaining non-matched test cases:

[  FAILED  ] Server_Test.Simple_Structs (2181 ms)