tests/tcg: Do not require FE_TOWARDZERO

This is optional in ISO C, and not all cpus provide it.

Tested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tests/tcg/multiarch/float_convs.c

@@ -30,7 +30,9 @@ float_mapping round_flags[] = {
 #ifdef FE_DOWNWARD
     { FE_DOWNWARD, "downwards" },
 #endif
+#ifdef FE_TOWARDZERO
     { FE_TOWARDZERO, "to zero" }
+#endif
 };
 
 static void print_input(float input)

tests/tcg/multiarch/float_madds.c

@@ -29,7 +29,9 @@ float_mapping round_flags[] = {
 #ifdef FE_DOWNWARD
     { FE_DOWNWARD, "downwards" },
 #endif
+#ifdef FE_TOWARDZERO
     { FE_TOWARDZERO, "to zero" }
+#endif
 };