tests: handle another truncation warning

MSVC flags this truncation as the size of the file is tracked as a
`uint64_t`, which is then used to construct a tuple where the size
is used in a field marked as `int`, resulting in a truncation if a
large file is encountered (which we know to not be the case here).
This statically casts away the truncation to silence it.
diff --git a/tests/bloaty_test.cc b/tests/bloaty_test.cc
index 2783ac8..8187aca 100644
--- a/tests/bloaty_test.cc
+++ b/tests/bloaty_test.cc
@@ -253,8 +253,9 @@
   ASSERT_TRUE(GetFileSize(file1, &size1));
   ASSERT_TRUE(GetFileSize(file2, &size2));
   RunBloaty({"bloaty", file1, file2, "-d", "inputfiles"});
-  AssertChildren(*top_row_, {std::make_tuple(file1, kUnknown, size1),
-                             std::make_tuple(file2, kUnknown, size2)});
+  AssertChildren(*top_row_,
+                 {std::make_tuple(file1, kUnknown, static_cast<int>(size1)),
+                  std::make_tuple(file2, kUnknown, static_cast<int>(size2))});
 
   // Should work with custom data sources.
   bloaty::Options options;
@@ -273,8 +274,8 @@
   )", &options);
 
   RunBloatyWithOptions(options, bloaty::OutputOptions());
-  AssertChildren(*top_row_,
-                 {std::make_tuple("binary", kUnknown, size1 + size2)});
+  AssertChildren(*top_row_, {std::make_tuple("binary", kUnknown,
+                                             static_cast<int>(size1 + size2))});
 }
 
 TEST_F(BloatyTest, DiffMode) {