Update on "[inductor] Clear cache on ctx manager exit"

FIXES #126128.

Right now, we only clear the cache on ctx manager enter. So state is bad unless we call fresh_inductor_cache again,  usually fine in tests.

Cue compiled autograd tests when going from TestCompiledAutograd -> TestAutogradWithCompiledAutograd. 
TestCompiledAutograd uses the ctx manager, but TestAutogradWithCompiledAutograd don't

cc voznesenskym penguinwu EikanWang jgong5 Guobing-Chen XiaobingSuper zhuhaozhe blzheng wenzhe-nrv jiayisunx peterbell10 ipiszy yf225 chenyang78 kadeng muchulee8 ColinPeppler amjames desertfire chauhang

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