tests: remove GCC < 4 fallbacks

Since commit efc6c07 ("configure: Add a test for the minimum compiler
version"), QEMU explicitely depends on GCC >= 4.8.

(clang >= 3.4 advertizes itself as GCC >= 4.2 compatible)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20201210134752.780923-6-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tests/tcg/arm/fcvt.c

@@ -73,11 +73,9 @@ static void print_int64(int i, int64_t num)
 
 #ifndef SNANF
 /* Signaling NaN macros, if supported.  */
-# if __GNUC_PREREQ(3, 3)
-#  define SNANF (__builtin_nansf (""))
-#  define SNAN (__builtin_nans (""))
-#  define SNANL (__builtin_nansl (""))
-# endif
+# define SNANF (__builtin_nansf (""))
+# define SNAN (__builtin_nans (""))
+# define SNANL (__builtin_nansl (""))
 #endif
 
 float single_numbers[] = { -SNANF,