FreeRTOS_ND_utest: Fix test failures due to missing initialization

test_SendPingRequestIPv6_SendToIP_Pass():
This test segfaulted without AddressSanitizer:

    'build/normal/bin/tests/FreeRTOS…' terminated by signal SIGSEGV

test_SendPingRequestIPv6_Assert():

    ==7143==AddressSanitizer CHECK failed: ../../../../src/libsanitizer/asan/asan_descriptions.cpp:80 "((0 && "Address is not in memory and not in shadow?")) != (0)" (0x0, 0x0)
    #0 0x7ff6c812f9a8 in AsanCheckFailed ../../../../src/libsanitizer/asan/asan_rtl.cpp:74
    FreeRTOS#1 0x7ff6c815032e in __sanitizer::CheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) ../../../../src/libsanitizer/sanitizer_common/sanitizer_termination.cpp:78
    FreeRTOS#2 0x7ff6c809fa77 in GetShadowKind ../../../../src/libsanitizer/asan/asan_descriptions.cpp:80
    FreeRTOS#3 0x7ff6c809fa77 in __asan::GetShadowAddressInformation(unsigned long, __asan::ShadowAddressDescription*) ../../../../src/libsanitizer/asan/asan_descriptions.cpp:96
    FreeRTOS#4 0x7ff6c809fa77 in __asan::GetShadowAddressInformation(unsigned long, __asan::ShadowAddressDescription*) ../../../../src/libsanitizer/asan/asan_descriptions.cpp:93
    FreeRTOS#5 0x7ff6c80a1296 in __asan::AddressDescription::AddressDescription(unsigned long, unsigned long, bool) ../../../../src/libsanitizer/asan/asan_descriptions.cpp:441
    FreeRTOS#6 0x7ff6c80a3a84 in __asan::ErrorGeneric::ErrorGeneric(unsigned int, unsigned long, unsigned long, unsigned long, unsigned long, bool, unsigned long) ../../../../src/libsanitizer/asan/asan_errors.cpp:389
    FreeRTOS#7 0x7ff6c812efc5 in __asan::ReportGenericError(unsigned long, unsigned long, unsigned long, unsigned long, bool, unsigned long, unsigned int, bool) ../../../../src/libsanitizer/asan/asan_report.cpp:476
    FreeRTOS#8 0x7ff6c80abc44 in __interceptor_memset ../../../../src/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:799
    FreeRTOS#9 0x55f2e38a3620 in FreeRTOS_SendPingRequestIPv6 build/u22/Annexed_TCP_Sources/FreeRTOS_ND.c:768
    FreeRTOS#10 0x55f2e3893053 in test_SendPingRequestIPv6_Assert test/unit-test/FreeRTOS_ND/FreeRTOS_ND_utest.c:1065
    FreeRTOS#11 0x55f2e389c5dd in run_test build/u22/FreeRTOS_ND_utest_runner.c:201
    FreeRTOS#12 0x55f2e389ca84 in main build/u22/FreeRTOS_ND_utest_runner.c:252
    FreeRTOS#13 0x7ff6c6bcbd8f  (/lib/x86_64-linux-gnu/libc.so.6+0x29d8f)
    FreeRTOS#14 0x7ff6c6bcbe3f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e3f)
    FreeRTOS#15 0x55f2e38873d4 in _start (build/u22/bin/tests/FreeRTOS_ND_utest+0x233d4

test_prvProcessICMPMessage_IPv6_NeighborSolicitationNullEP()
behaved different with and without ASan on Gcc 11.
Without AddressSanitizer on Gcc 11:

    FreeRTOS_ND_utest.c:1427:test_prvProcessICMPMessage_IPv6_NeighborSolicitationNullEP:
    FAIL:Function usGenerateProtocolChecksum.  Called more times than expected.

test/unit-test/FreeRTOS_ND/FreeRTOS_ND_utest.c

@@ -1039,15 +1039,16 @@ void test_SendPingRequestIPv6_NULL_Buffer( void )
  */
 void test_SendPingRequestIPv6_Assert( void )
 {
-    NetworkEndPoint_t xEndPoint, * pxEndPoint = &xEndPoint;
-    NetworkBufferDescriptor_t xNetworkBuffer, * pxNetworkBuffer = &xNetworkBuffer;
+    NetworkEndPoint_t xEndPoint = { 0 }, * pxEndPoint = &xEndPoint;
+    NetworkBufferDescriptor_t xNetworkBuffer = { 0 };
     uint8_t ucEthernetBuffer[ 1500 ] = { 0 };
-    IPv6_Address_t xIPAddress;
+    IPv6_Address_t xIPAddress = { 0 };
     size_t uxNumberOfBytesToSend = 100;
     BaseType_t xReturn;
     uint16_t usSequenceNumber = 1;
 
     xNetworkBuffer.pucEthernetBuffer = ucEthernetBuffer;
+    xNetworkBuffer.xDataLength = sizeof( ucEthernetBuffer );
     ( void ) memcpy( xIPAddress.ucBytes, xDefaultIPAddress.ucBytes, ipSIZE_OF_IPv6_ADDRESS );
 
     pxEndPoint->bits.bIPv6 = 1;
@@ -1059,7 +1060,7 @@ void test_SendPingRequestIPv6_Assert( void )
 
 
     uxGetNumberOfFreeNetworkBuffers_ExpectAndReturn( 4U );
-    pxGetNetworkBufferWithDescriptor_ExpectAnyArgsAndReturn( pxNetworkBuffer );
+    pxGetNetworkBufferWithDescriptor_ExpectAnyArgsAndReturn( &xNetworkBuffer );
     xSendEventStructToIPTask_IgnoreAndReturn( pdPASS );
 
     xReturn = FreeRTOS_SendPingRequestIPv6( &xIPAddress, uxNumberOfBytesToSend, 0 );
@@ -1075,14 +1076,15 @@ void test_SendPingRequestIPv6_Assert( void )
 void test_SendPingRequestIPv6_SendToIP_Pass( void )
 {
     NetworkEndPoint_t xEndPoint, * pxEndPoint = &xEndPoint;
-    NetworkBufferDescriptor_t xNetworkBuffer, * pxNetworkBuffer = &xNetworkBuffer;
+    NetworkBufferDescriptor_t xNetworkBuffer = { 0 }, * pxNetworkBuffer = &xNetworkBuffer;
     uint8_t ucEthernetBuffer[ 1500 ] = { 0 };
     IPv6_Address_t xIPAddress;
     size_t uxNumberOfBytesToSend = 100;
     BaseType_t xReturn;
     uint16_t usSequenceNumber = 1;
 
     xNetworkBuffer.pucEthernetBuffer = ucEthernetBuffer;
+    xNetworkBuffer.xDataLength = sizeof( ucEthernetBuffer );
     ( void ) memcpy( xIPAddress.ucBytes, xDefaultIPAddress.ucBytes, ipSIZE_OF_IPv6_ADDRESS );
 
     pxEndPoint->bits.bIPv6 = 1;
@@ -1460,15 +1462,17 @@ void test_prvProcessICMPMessage_IPv6_ipICMP_PING_REPLY_IPv6_eSuccess( void )
  */
 void test_prvProcessICMPMessage_IPv6_NeighborSolicitationNullEP( void )
 {
-    NetworkBufferDescriptor_t xNetworkBuffer, * pxNetworkBuffer = &xNetworkBuffer;
-    ICMPPacket_IPv6_t xICMPPacket;
-    NetworkEndPoint_t xEndPoint;
+    NetworkBufferDescriptor_t xNetworkBuffer = { 0 }, * pxNetworkBuffer = &xNetworkBuffer;
+    ICMPPacket_IPv6_t xICMPPacket = { 0 };
+    NetworkEndPoint_t xEndPoint = { 0 };
     eFrameProcessingResult_t eReturn;
 
     xEndPoint.bits.bIPv6 = pdTRUE_UNSIGNED;
+    ( void ) memcpy( xEndPoint.ipv6_settings.xIPAddress.ucBytes, xDefaultIPAddress.ucBytes, ipSIZE_OF_IPv6_ADDRESS );
     xICMPPacket.xICMPHeaderIPv6.ucTypeOfMessage = ipICMP_NEIGHBOR_SOLICITATION_IPv6;
     pxNetworkBuffer->pxEndPoint = &xEndPoint;
     pxNetworkBuffer->pucEthernetBuffer = ( uint8_t * ) &xICMPPacket;
+    pxNetworkBuffer->xDataLength = sizeof( xICMPPacket );
 
     FreeRTOS_InterfaceEPInSameSubnet_IPv6_ExpectAnyArgsAndReturn( NULL );