Disable run-tests causing occasional timeouts with CC.

These tests sometimes time out on the concurrent collector
configurations:
- 004-ThreadStress
- 496-checker-inlining-and-class-loader

Disable them while we investigate.

Bug: 26786154
Bug: 26786304
Bug: 12687968
Change-Id: I169766eac656cd1281a169337c2205a9592c32a1