add missing file newlines

Author: rok-cesnovar

test/unit/math/prim/fun/asin_test.cpp

@@ -4,4 +4,4 @@
 TEST(primScalFun, asin) {
   stan::test::expect_common_prim([](auto x) { return std::asin(x); },
                                  [](auto x) { return stan::math::asin(x); });
-}
+}

test/unit/math/prim/fun/atan_test.cpp

@@ -4,4 +4,4 @@
 TEST(primScalFun, atan) {
   stan::test::expect_common_prim([](auto x) { return std::atan(x); },
                                  [](auto x) { return stan::math::atan(x); });
-}
+}