Build bionic unit tests for musl

Modify bionic unit tests that are built for glibc so that they also
build against musl.  They don't all pass though:

With glibc:
 2 SLOW TESTS
 4 TIMEOUT TESTS
313 FAILED TESTS
  YOU HAVE 2 DISABLED TESTS

With musl:
11 SLOW TESTS
11 TIMEOUT TESTS
363 FAILED TESTS
  YOU HAVE 2 DISABLED TESTS

Bug: 190084016
Test: m bionic-unit-tests-glibc with musl
Test: atest bionic-unit-tests-static
Test: atest --host bionic-unit-tests-glibc with glibc
Change-Id: I79b6eab04fed3cc4392450df5eef2579412edfe1
diff --git a/tests/ftw_test.cpp b/tests/ftw_test.cpp
index 200ed4b..6473f71 100644
--- a/tests/ftw_test.cpp
+++ b/tests/ftw_test.cpp
@@ -106,7 +106,7 @@
   ASSERT_EQ(0, ftw(root.path, check_ftw, 128));
 }
 
-TEST(ftw, ftw64) {
+TEST(ftw, ftw64_smoke) {
   TemporaryDir root;
   MakeTree(root.path);
   ASSERT_EQ(0, ftw64(root.path, check_ftw64, 128));
@@ -118,7 +118,7 @@
   ASSERT_EQ(0, nftw(root.path, check_nftw, 128, 0));
 }
 
-TEST(ftw, nftw64) {
+TEST(ftw, nftw64_smoke) {
   TemporaryDir root;
   MakeTree(root.path);
   ASSERT_EQ(0, nftw64(root.path, check_nftw64, 128, 0));