BLIS GTestSuite Updates:

- Fix in README.md.
- Updating abs overload for scomplex and dcomplex to avoid overflow by using std::abs.
- Updating comparators to take into account NaNs and Infs when measuring error.

AMD-Internal: [CPUPL-2732]
Change-Id: I8c12bacd9d63b2e914d0a79f337f7525dc16b733

gtestsuite/testinghelpers/inc/common/complex_helpers.h

@@ -60,4 +60,23 @@ bool operator== (const scomplex x, const scomplex y);
 bool operator== (const dcomplex x, const dcomplex y);
 
 bool operator!= (const scomplex x, const scomplex y);
-bool operator!= (const dcomplex x, const dcomplex y);
+bool operator!= (const dcomplex x, const dcomplex y);
+
+// Since we may only specialise template functions and classes 
+// in the std namespace for custom types, and std::to_string is not 
+// a template function, we put to_string into our namespace.
+namespace testinghelpers {
+template<typename T>    
+std::string to_string(const T& x) {
+    if constexpr (testinghelpers::type_info<T>::is_complex)
+    {   
+        std::string ss = "(" + std::to_string(x.real) + ", " + std::to_string(x.imag) + ")";
+        return ss;
+    }
+    else
+    {
+        return std::to_string(x);
+    }
+}
+
+}