Eliminate double-promotion warnings.
Clang currently complains about implicit conversions, e.g.
```
test/packetmath.cpp:680:59: warning: implicit conversion increases floating-point precision: 'typename Eigen::internal::random_retval<typename Eigen::internal::global_math_functions_filtering_base<double>::type>::type' (aka 'double') to 'long double' [-Wdouble-promotion]
data1[0] = Scalar((2 * k + k1) * EIGEN_PI / 2 * internal::random<double>(0.8, 1.2));
~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test/packetmath.cpp:681:40: warning: implicit conversion increases floating-point precision: 'float' to 'long double' [-Wdouble-promotion]
data1[1] = Scalar((2 * k + 2 + k1) * EIGEN_PI / 2 * internal::random<double>(0.8, 1.2));
```
Modified to explicitly cast to double.
diff --git a/test/packetmath.cpp b/test/packetmath.cpp
index eabf69c..81425b8 100644
--- a/test/packetmath.cpp
+++ b/test/packetmath.cpp
@@ -677,8 +677,8 @@
test::packet_helper<PacketTraits::HasCos, Packet> h;
for (Scalar k = Scalar(1); k < Scalar(10000) / std::numeric_limits<Scalar>::epsilon(); k *= Scalar(2)) {
for (int k1 = 0; k1 <= 1; ++k1) {
- data1[0] = Scalar((2 * k + k1) * EIGEN_PI / 2 * internal::random<double>(0.8, 1.2));
- data1[1] = Scalar((2 * k + 2 + k1) * EIGEN_PI / 2 * internal::random<double>(0.8, 1.2));
+ data1[0] = Scalar((2 * double(k) + k1) * double(EIGEN_PI) / 2 * internal::random<double>(0.8, 1.2));
+ data1[1] = Scalar((2 * double(k) + 2 + k1) * double(EIGEN_PI) / 2 * internal::random<double>(0.8, 1.2));
h.store(data2, internal::pcos(h.load(data1)));
h.store(data2 + PacketSize, internal::psin(h.load(data1)));
VERIFY(data2[0] <= Scalar(1.) && data2[0] >= Scalar(-1.));
