The GPL states that if you fail to grant downstream users rights to use and redistribute the code (which includes any patented code contributed by the patent holder to the product from any party that did it, not only Oracle) you cannot distribute your code under the GPL.
If Oracle included patented technology it did not control, then it must stop distribution of infringing code under the GPL. That's one of the reasons it took so long for Sun to license its code under GPL - it was cleaning up code, removing patent-infringing code.
The terms of the TCK will not protect you from lawsuits for infringing on patents Oracle had not the right to grant you usage. In fact, no agreement with Oracle would.
If Oracle included patented technology it did not control, then it must stop distribution of infringing code under the GPL. That's one of the reasons it took so long for Sun to license its code under GPL - it was cleaning up code, removing patent-infringing code.
The terms of the TCK will not protect you from lawsuits for infringing on patents Oracle had not the right to grant you usage. In fact, no agreement with Oracle would.