BYT IVB : igt@gem_ctx_isolation@preservation-reset@rcs0 - Failed assertion: num_errors == 0, +\d registers mistached between dirty .* context

https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_754/fi-ivb-3770/igt@gem_ctx_isolation@preservation-reset@rcs0.html

- Err	
- Starting subtest: preservation-reset
- Starting dynamic subtest: rcs0
- (gem_ctx_isolation:2469) WARNING: Register 0x20c0 (INSTPM): A=00000280 B=00000000
- (gem_ctx_isolation:2469) WARNING: Register 0x7000 (Cache_Mode_0): A=00006804 B=00000000
- (gem_ctx_isolation:2469) WARNING: Register 0x7004 (Cache_Mode_1): A=000001c0 B=00000000
- (gem_ctx_isolation:2469) CRITICAL: Test assertion failure function compare_regs, file ../tests/i915/gem_ctx_isolation.c:595:
- (gem_ctx_isolation:2469) CRITICAL: Failed assertion: num_errors == 0
- (gem_ctx_isolation:2469) CRITICAL: 3 registers mistached between dirty cccccccc context
- .
- Dynamic subtest rcs0 failed.