Added Unix Implementations for Extracting Elements of addrInfo

To extract length, family, socktype, protocol from addrInfo of OMRAddrInfoNode struct

- The OMRAddrInfoNode has two elements, which first one, addrInfo,
  is a pointer to the first addrinfo node in a linked list.
- The Unix addrinfo structs contains many elements which stores
  a variety of information about a socket address.
- Extracts unix addrinfo elements by passing in a pointer to a
  OMRAddrInfoNode and the index of which one of the linked list of
  addrinfo nodes to extract.
- Currently implemented the element extractions of what is needed
  to create a socket.

Issue: eclipse-omr#4745

Depends on PR:eclipse-omr#4555

Signed-off-by: Haley Cao <haleycao88@hotmail.com>

port/unix/omrsock.c

@@ -82,25 +82,50 @@ omrsock_getaddrinfo(struct OMRPortLibrary *portLibrary, char *node, char *servic
 int32_t
 omrsock_getaddrinfo_length(struct OMRPortLibrary *portLibrary, omrsock_addrinfo_t handle, uint32_t *length)
 {
-	return OMRPORT_ERROR_NOT_SUPPORTED_ON_THIS_PLATFORM;
+	*length = handle->length;
+	return 0;
 }
 
 int32_t
 omrsock_getaddrinfo_family(struct OMRPortLibrary *portLibrary, omrsock_addrinfo_t handle, int32_t *family, int32_t index)
 {
-	return OMRPORT_ERROR_NOT_SUPPORTED_ON_THIS_PLATFORM;
+	omr_os_addrinfo *info = handle->addrInfo;
+	int32_t i = 0;
+
+	for(i = 0; i < index; i++) {
+		info = info->ai_next;
+	}
+
+	*family = info->ai_family;
+	return 0;
 }
 
 int32_t
 omrsock_getaddrinfo_socktype(struct OMRPortLibrary *portLibrary, omrsock_addrinfo_t handle, int32_t *socktype, int32_t index)
 {
-	return OMRPORT_ERROR_NOT_SUPPORTED_ON_THIS_PLATFORM;
+	omr_os_addrinfo *info = handle->addrInfo;
+	int32_t i = 0;
+
+	for(i = 0; i < index; i++) {
+		info = info->ai_next;
+	}
+
+	*socktype = info->ai_socktype;
+	return 0;
 }
 
 int32_t
 omrsock_getaddrinfo_protocol(struct OMRPortLibrary *portLibrary, omrsock_addrinfo_t handle, int32_t *protocol, int32_t index)
 {
-	return OMRPORT_ERROR_NOT_SUPPORTED_ON_THIS_PLATFORM;
+	omr_os_addrinfo *info = handle->addrInfo;
+	int32_t i = 0;	
+
+	for(i = 0; i < index; i++) {
+		info = info->ai_next;
+	}
+
+	*protocol = info->ai_protocol;
+	return 0;
 }
 
 int32_t