Quick disable of NPAPI browser tests that are failing on win8_chromium_gn bot.

The NPAPI test plugin isn't built in GN, so the bots fail if the plugin didn't happen to be already there from gyp.

More thorough removal is in https://codereview.chromium.org/1182303010

BUG=493212, 497423
TBR=dpranke

Review URL: https://codereview.chromium.org/1185303002

Cr-Commit-Position: refs/heads/master@{#334597}
2 files changed