tests: add API_REGISTER_STATE_CHECK

used to wrap API functions to ensure full environment consistency as
opposed to the renamed ASM_REGISTER_STATE_CHECK which is used with
assembly functions.
currently checks the FPU tag word in x86/x86_64 gcc builds to ensure
emms has been called.

Change-Id: Ie241772dbf903d33d516a1add4c8c6783f2e1490

test/decode_test_driver.cc

@@ -32,7 +32,7 @@ vpx_codec_err_t Decoder::DecodeFrame(const uint8_t *cxdata, size_t size,
                                      void *user_priv) {
   vpx_codec_err_t res_dec;
   InitOnce();
-  REGISTER_STATE_CHECK(
+  API_REGISTER_STATE_CHECK(
       res_dec = vpx_codec_decode(&decoder_,
                                  cxdata, static_cast<unsigned int>(size),
                                  user_priv, 0));