changes towards a canonical representation of comparisons: * new createNullCheckGuard helper method on CiLoweringTool * replaced NullCheckNode with IsNullNode * GuardNode and FixedGuardNode can be negated * keep a list of conditions that are true/false in CheckCastEliminationPhase * FixedGuardNode has only one condition * GraphBuilderPhase creates canonical CompareNodes * BooleanNodes can negate their usages * added junit test for canonicalized compares * removed junit test for negated instanceof * added more thorough graph comparison for junit tests * CheckCastEliminationPhase keeps track of conditions that are known to be true/false

colorize("name", ".*", white);
colorize("name", "Begin|EndNode|LoopBegin|LoopEnd|LoopExit|Return", orange);
colorize("name", "Phi.*|ValueProxy", magenta);
colorize("name", "FrameState@.*", new java.awt.Color(0.5, 0.8, 1.0));
colorize("name", "If|Merge", pink);
colorize("name", "const.*", new java.awt.Color(0.7, 0.7, 0.7));
colorize("name", "Local", new java.awt.Color(0.85, 0.85, 0.85));
colorize("name", "\\+|-|\\*|/|&|\\||<<|>>|>>>", cyan);
colorize("name", "Comp .*", yellow);
colorize("name", "Virtual.*", green);

colorize("notInOwnBlock", "true", red);