[graph] csr_graph_test failing on MSVC

[Richard Webb <richard.webb@…>]

The csr_graph_test test is failing on the MS compilers due to a conflict between std::numeric_limits<T>::max and the max macro -> see ​http://tinyurl.com/3g22uxe for the official test results.

changing line 27 of relax.hpp from

closed_plus() : inf(std::numeric_limits<T>::max()) { }

to

closed_plus() : inf((std::numeric_limits<T>::max)()) { }

allows the test to pass.

[Jeremiah Willcock]

(In [74075]) Added parentheses around call to numeric_limits::max; fixes #5813