Add tests for all C11 headers.

Well, all except <threads.h> which we have no current plans to implement.

The only thing this turned up is that clang's <float.h> doesn't define
FLT_HAS_SUBNORM/DBL_HAS_SUBNORM/LDBL_HAS_SUBNORM, so for now we assert
that those are missing so that when we get a fixed clang, we notice.

Also the <tgmath.h> is utterly perfunctory, but seems like an appropriate
amount of effort to put in.

Bug: N/A
Test: ran tests
Change-Id: I7f7a7040b3271ceda625bee8a40a9d8cef52ee44
diff --git a/tests/Android.bp b/tests/Android.bp
index b5f8dc8..6b96e24 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -66,6 +66,7 @@
         "eventfd_test.cpp",
         "fcntl_test.cpp",
         "fenv_test.cpp",
+        "float_test.cpp",
         "ftw_test.cpp",
         "getauxval_test.cpp",
         "getcwd_test.cpp",
@@ -73,10 +74,12 @@
         "iconv_test.cpp",
         "ifaddrs_test.cpp",
         "inttypes_test.cpp",
+        "iso646_test.c",
         "langinfo_test.cpp",
         "leak_test.cpp",
         "libgen_basename_test.cpp",
         "libgen_test.cpp",
+        "limits_test.cpp",
         "linux_swab_test.cpp",
         "locale_test.cpp",
         "malloc_test.cpp",
@@ -102,12 +105,16 @@
         "stack_protector_test.cpp",
         "stack_protector_test_helper.cpp",
         "stack_unwinding_test.cpp",
+        "stdalign_test.cpp",
+        "stdarg_test.cpp",
         "stdatomic_test.cpp",
+        "stdbool_test.c",
         "stdint_test.cpp",
         "stdio_nofortify_test.cpp",
         "stdio_test.cpp",
         "stdio_ext_test.cpp",
         "stdlib_test.cpp",
+        "stdnoreturn_test.cpp",
         "string_nofortify_test.cpp",
         "string_test.cpp",
         "string_posix_strerror_r_test.cpp",
@@ -142,6 +149,7 @@
         "sys_xattr_test.cpp",
         "system_properties_test.cpp",
         "system_properties_test2.cpp",
+        "tgmath_test.c",
         "time_test.cpp",
         "uchar_test.cpp",
         "unistd_nofortify_test.cpp",