[foozzie] Add some system tests.

tools/foozzie/testdata/failure_output.txt

+#
+# V8 correctness failure
+# V8 correctness configs: x64,fullcode:x64,ignition_staging
+# V8 correctness sources: 
+# V8 correctness suppression: 
+#
+# CHECK
+#
+# Compared x64,fullcode with x64,ignition_staging
+#
+# Flags of x64,fullcode:
+--abort_on_stack_overflow --expose-gc --allow-natives-syntax --invoke-weak-callbacks --omit-quit --es-staging --random-seed 12345 --nocrankshaft --turbo-filter=~
+# Flags of x64,ignition_staging:
+--abort_on_stack_overflow --expose-gc --allow-natives-syntax --invoke-weak-callbacks --omit-quit --es-staging --random-seed 12345 --ignition-staging
+#
+# Difference:
+- unknown
++ not unknown
+#
+### Start of configuration x64,fullcode:
+
+1
+2
+  weird error
+        ^
+3
+unknown
+
+
+### End of configuration x64,fullcode
+#
+### Start of configuration x64,ignition_staging:
+
+1
+2
+  weird other error
+^
+3
+not unknown
+
+
+### End of configuration x64,ignition_staging
+