Replace std::numeric_limits<>::infinity() with max() (#4547)

If fast-math is enabled from #4545, calculations with
`std::numeric_limits<>::infinity()` won't work due to the implied
`-ffinite-math-only` flag.

Author: AlexanderSinn

Src/Base/AMReX_CoordSys.H

@@ -241,9 +241,9 @@ protected:
 
     Real dx[AMREX_SPACEDIM] = {AMREX_D_DECL(0.,0.,0.)};
     Real inv_dx[AMREX_SPACEDIM]
-        = {AMREX_D_DECL(std::numeric_limits<Real>::infinity(),
-                        std::numeric_limits<Real>::infinity(),
-                        std::numeric_limits<Real>::infinity())};
+        = {AMREX_D_DECL(std::numeric_limits<Real>::max(),
+                        std::numeric_limits<Real>::max(),
+                        std::numeric_limits<Real>::max())};
     bool ok = false;
 };