RFR(XXS): 8151795: compiler/compilercontrol/parser/DirectiveParserTest.java fails with "assert failed: 0 != 0"

[Nils Eliasson]

Hi,

Summary:
Adding directives from diagnostic command should treat zero directives 
in file as failure.

Bug: https://bugs.openjdk.java.net/browse/JDK-8151795
Webrev: http://cr.openjdk.java.net/~neliasso/8151795/webrev.01/

Regards,
Nils Eliasson