Adjust test expectations to match the guix platform
--- a/tests/t251_exception4.py
+++ b/tests/t251_exception4.py
@@ -5,16 +5,18 @@ from runtest import TestBase
 class TestCase(TestBase):
     def __init__(self):
         TestBase.__init__(self, 'libexcept-main', lang='C++', result="""
-# DURATION    TID     FUNCTION
-            [423633] | main() {
-            [423633] |   XXX::XXX() {
-  30.679 us [423633] |     XXX::XXX();
-  31.490 us [423633] |   } /* XXX::XXX */
-            [423633] |   YYY::YYY() {
-   0.509 us [423633] |     __cxa_allocate_exception();
-   0.541 us [423633] |     std::runtime_error::runtime_error();
-   5.670 us [423633] |   } /* YYY::YYY */
-  42.354 us [423633] | } /* main */
+# DURATION     TID     FUNCTION
+            [ 39887] | main() {
+            [ 39887] |   XXX::XXX() {
+  35.591 us [ 39887] |     XXX::XXX();
+  36.215 us [ 39887] |   } /* XXX::XXX */
+   5.617 us [ 39887] |   std::runtime_error::~runtime_error();
+            [ 39887] |   YYY::YYY() {
+   0.291 us [ 39887] |     __cxa_allocate_exception();
+   0.399 us [ 39887] |     std::runtime_error::runtime_error();
+   3.683 us [ 39887] |   } /* YYY::YYY */
+   0.122 us [ 39887] |   std::runtime_error::~runtime_error();
+  48.809 us [ 39887] | } /* main */
 """)
 
     def build(self, name, cflags='', ldflags=''):
