COMPMID-724: Moved exception throwing to Error.cpp

This is to make Error.h compliant with the no-exception policy in Android

Change-Id: Ice73800ae1559406cb6ffe54dad9861e869894ef
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/111585
Reviewed-by: Gian Marco Iodice <gianmarco.iodice@arm.com>
Tested-by: BSG Visual Compute Jenkins server to access repositories on http://mpd-gerrit.cambridge.arm.com <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
diff --git a/arm_compute/core/Error.h b/arm_compute/core/Error.h
index 277db9d..bd80aa4 100644
--- a/arm_compute/core/Error.h
+++ b/arm_compute/core/Error.h
@@ -25,7 +25,6 @@
 #define __ARM_COMPUTE_ERROR_H__
 
 #include <stdarg.h>
-#include <stdexcept>
 #include <string>
 
 namespace arm_compute
@@ -97,10 +96,7 @@
 
 private:
     /** Internal throwing function */
-    [[noreturn]] void internal_throw_on_error()
-    {
-        throw std::runtime_error(_description);
-    }
+    [[noreturn]] void internal_throw_on_error();
 
 private:
     ErrorCode   _code;
diff --git a/src/core/Error.cpp b/src/core/Error.cpp
index 3b0a012..be362bb 100644
--- a/src/core/Error.cpp
+++ b/src/core/Error.cpp
@@ -56,3 +56,7 @@
     va_end(args);
     throw std::runtime_error(err.description());
 }
+void Error::internal_throw_on_error()
+{
+    throw std::runtime_error(_description);
+}