Only test pi if float is smaller than long double

test/unit_test/runtime/magnitude_test.cpp

@@ -163,6 +163,7 @@ TEST_CASE("magnitude converts to numerical value")
 
   SECTION("pi to arbitrary power performs computations in most accurate type at compile time")
   {
+    if constexpr (sizeof(float) < sizeof(long double)) {
       constexpr auto pi_cubed = pi_to_the<3>();
 
       auto cube = [](auto x) { return x * x * x; };
@@ -173,6 +174,7 @@ TEST_CASE("magnitude converts to numerical value")
       REQUIRE(pi_cubed_value != via_float);
       CHECK(pi_cubed_value == via_long_double);
     }
+  }
 
   SECTION("Impossible requests are prevented at compile time")
   {