TS-3827: Add tests for http2_are_frame_flags_valid
TS-3827: Add tests for http2_are_frame_flags_valid

This closes #295

bryancall/trafficserver,taoyunxing/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,taoyunxing/trafficserver,chenglongwei/trafficserver,vmamidi/trafficserver,persiaAziz/trafficserver,rahmalik/trafficserver,duke8253/trafficserver,taoyunxing/trafficserver,reveller/trafficserver,chitianhao/trafficserver,duke8253/trafficserver,chitianhao/trafficserver,bryancall/trafficserver,taoyunxing/trafficserver,dyrock/trafficserver,pbchou/trafficserver,rpufky/trafficserver,dyrock/trafficserver,pbchou/trafficserver,chitianhao/trafficserver,rahmalik/trafficserver,rpufky/trafficserver,dyrock/trafficserver,chenglongwei/trafficserver,duke8253/trafficserver,dyrock/trafficserver,rahmalik/trafficserver,reveller/trafficserver,vmamidi/trafficserver,PSUdaemon/trafficserver,clearswift/trafficserver,clearswift/trafficserver,pbchou/trafficserver,chenglongwei/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,reveller/trafficserver,rpufky/trafficserver,SolidWallOfCode/trafficserver,persiaAziz/trafficserver,persiaAziz/trafficserver,rpufky/trafficserver,PSUdaemon/trafficserver,chenglongwei/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,persiaAziz/trafficserver,pbchou/trafficserver,rahmalik/trafficserver,rahmalik/trafficserver,persiaAziz/trafficserver,rahmalik/trafficserver,reveller/trafficserver,SolidWallOfCode/trafficserver,taoyunxing/trafficserver,davidbz/trafficserver,rahmalik/trafficserver,PSUdaemon/trafficserver,persiaAziz/trafficserver,duke8253/trafficserver,dyrock/trafficserver,davidbz/trafficserver,bryancall/trafficserver,clearswift/trafficserver,taoyunxing/trafficserver,davidbz/trafficserver,chenglongwei/trafficserver,chitianhao/trafficserver,rahmalik/trafficserver,chenglongwei/trafficserver,chenglongwei/trafficserver,taoyunxing/trafficserver,reveller/trafficserver,vmamidi/trafficserver,vmamidi/trafficserver,PSUdaemon/trafficserver,reveller/trafficserver,pbchou/trafficserver,chitianhao/trafficserver,pbchou/trafficserver,davidbz/trafficserver,rpufky/trafficserver,vmamidi/trafficserver,persiaAziz/trafficserver,rpufky/trafficserver,reveller/trafficserver,clearswift/trafficserver,taoyunxing/trafficserver,taoyunxing/trafficserver,chitianhao/trafficserver,SolidWallOfCode/trafficserver,vmamidi/trafficserver,rahmalik/trafficserver,clearswift/trafficserver,davidbz/trafficserver,clearswift/trafficserver,clearswift/trafficserver,PSUdaemon/trafficserver,reveller/trafficserver,bryancall/trafficserver,dyrock/trafficserver,clearswift/trafficserver,duke8253/trafficserver,chitianhao/trafficserver,clearswift/trafficserver,duke8253/trafficserver,davidbz/trafficserver,dyrock/trafficserver,PSUdaemon/trafficserver,PSUdaemon/trafficserver,reveller/trafficserver,rpufky/trafficserver,rpufky/trafficserver,persiaAziz/trafficserver,PSUdaemon/trafficserver,chenglongwei/trafficserver,PSUdaemon/trafficserver,rpufky/trafficserver,SolidWallOfCode/trafficserver