Make sure that the same tests are on all platforms.

In order to be able to generate a list of tests for cts, the same set of
tests must exist across all platforms. This CL adds empty tests where a
test was conditionally compiled out.

This CL creates a single library libBionicTests that includes all of
the tests found in bionic-unit-tests-static.

Also fix a few missing include files in some test files.

Tested by running and compiling the tests for every platform and
verifying the same number of tests are on each platform.

Change-Id: I9989d4bfebb0f9c409a0ce7e87169299eac605a2

tests/sys_sendfile_test.cpp

@@ -42,7 +42,6 @@ TEST(sys_sendfile, sendfile) {
   ASSERT_STREQ("ll", buf);
 }
 
-#if __BIONIC__
 TEST(sys_sendfile, sendfile64) {
   TemporaryFile src_file;
   ASSERT_EQ(5, TEMP_FAILURE_RETRY(write(src_file.fd, "hello", 5)));
@@ -61,4 +60,3 @@ TEST(sys_sendfile, sendfile64) {
   ASSERT_EQ(2, TEMP_FAILURE_RETRY(read(dst_file.fd, &buf, 2)));
   ASSERT_STREQ("ll", buf);
 }
-#endif