Adds reporting of file/line no. in failed tests

Tests in tests/suites will now report the file and line number of
failed test assertions.
diff --git a/tests/suites/helpers.function b/tests/suites/helpers.function
index cc9ab7c..31b8f58 100644
--- a/tests/suites/helpers.function
+++ b/tests/suites/helpers.function
@@ -57,7 +57,7 @@
     do {                                            \
         if( ! (TEST) )                              \
         {                                           \
-            test_fail( #TEST );                     \
+            test_fail( #TEST, __LINE__, __FILE__ ); \
             goto exit;                              \
         }                                           \
     } while( 0 )
@@ -348,11 +348,11 @@
     return( 0 );
 }
 
-static void test_fail( const char *test )
+static void test_fail( const char *test, int line_no, char* filename )
 {
     test_errors++;
     if( test_errors == 1 )
         mbedtls_printf( "FAILED\n" );
-    mbedtls_printf( "  %s\n", test );
+    mbedtls_printf( "  %s\n  at line %d, %s\n", test, line_no, filename );
 }