[libc] Disable epoll_create fail test when SYS_epoll_create1 is used internally (#99785)

The fail test case only makes sense if SYS_epoll_create is used internally to implement epoll_create, since the only argument to epoll_create (size) is dropped if SYS_epoll_create1 is used.

Author: mikhailramalho

libc/test/src/sys/epoll/linux/epoll_create_test.cpp

@@ -10,6 +10,7 @@
 #include "src/unistd/close.h"
 #include "test/UnitTest/ErrnoSetterMatcher.h"
 #include "test/UnitTest/Test.h"
+#include <sys/syscall.h> // For syscall numbers.
 
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 
@@ -21,6 +22,8 @@ TEST(LlvmLibcEpollCreateTest, Basic) {
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds());
 }
 
+#ifdef SYS_epoll_create
 TEST(LlvmLibcEpollCreateTest, Fails) {
   ASSERT_THAT(LIBC_NAMESPACE::epoll_create(0), Fails(EINVAL));
 }
+#endif