[NaCl SDK] Temporarily disable host testing of pi_generator
[NaCl SDK] Temporarily disable host testing of pi_generator

Running this example is consistently failing under host mac
build and occasionally failing on linux as well.

CQ_EXTRA_TRYBOTS=tryserver.chromium.linux:linux_nacl_sdk;tryserver.chromium.mac:mac_nacl_sdk
BUG=475255

Review URL: https://codereview.chromium.org/1076573004

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#324361}

Fireblend/chromium-crosswalk,axinging/chromium-crosswalk,chuan9/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Just-D/chromium-1,PeterWangIntel/chromium-crosswalk,Pluto-tv/chromium-crosswalk,axinging/chromium-crosswalk,hgl888/chromium-crosswalk,Pluto-tv/chromium-crosswalk,axinging/chromium-crosswalk,Fireblend/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,chuan9/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,Just-D/chromium-1,PeterWangIntel/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Chilledheart/chromium,Just-D/chromium-1,Fireblend/chromium-crosswalk,Fireblend/chromium-crosswalk,Fireblend/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Chilledheart/chromium,ltilve/chromium,Just-D/chromium-1,axinging/chromium-crosswalk,chuan9/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Just-D/chromium-1,Pluto-tv/chromium-crosswalk,chuan9/chromium-crosswalk,axinging/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,ltilve/chromium,chuan9/chromium-crosswalk,ltilve/chromium,Chilledheart/chromium,ltilve/chromium,hgl888/chromium-crosswalk,hgl888/chromium-crosswalk,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,ltilve/chromium,Chilledheart/chromium,PeterWangIntel/chromium-crosswalk,chuan9/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Chilledheart/chromium,hgl888/chromium-crosswalk,Fireblend/chromium-crosswalk,Just-D/chromium-1,ltilve/chromium,ltilve/chromium,Chilledheart/chromium,Just-D/chromium-1,Pluto-tv/chromium-crosswalk,ltilve/chromium,axinging/chromium-crosswalk,axinging/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Pluto-tv/chromium-crosswalk,chuan9/chromium-crosswalk,axinging/chromium-crosswalk,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,Chilledheart/chromium,TheTypoMaster/chromium-crosswalk,hgl888/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,ltilve/chromium,Fireblend/chromium-crosswalk,Chilledheart/chromium,Just-D/chromium-1,Fireblend/chromium-crosswalk,Fireblend/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,hgl888/chromium-crosswalk,hgl888/chromium-crosswalk,axinging/chromium-crosswalk,TheTypoMaster/chromium-crosswalk