Introducing upgrated BLIS GTestSuite.

Key features:
- able to test both static and dynamic libraries
- able to test BLAS, CBLAS and BLIS-typed interface
- can use any CBLAS library for reference results
- can build and/or run tests depending on the BLAS level or a specific API

AMD-Internal: [CPUPL-2732]
Change-Id: Ibe0d7938e06081526bbc54d3182ac7d17affdaf6

gtestsuite/testinghelpers/inc/common/complex_helpers.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <iostream>
+#include "common/type_info.h"
+
+namespace std {
+    // Overload std::abs to work with scomplex and dcomplex.
+    float abs(const scomplex x);
+    double abs(const dcomplex x);
+    // Overload the stream operator to be able to print scomplex in error messages.
+    ostream& operator<<(ostream& os, const scomplex& x);
+    ostream& operator<<(ostream& os, const dcomplex& x);
+}
+
+// Operator overloading for scomplex and dcomplex types.
+scomplex operator+(const scomplex x, const scomplex y);
+dcomplex operator+(const dcomplex x, const dcomplex y);
+
+scomplex operator-(const scomplex x, const scomplex y);
+dcomplex operator-(const dcomplex x, const dcomplex y);
+
+scomplex operator*(const scomplex x, const scomplex y);
+dcomplex 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 scomplex x, const scomplex y);
+bool operator!= (const dcomplex x, const dcomplex y);