Auto merge of #3470 - nical:blob-eviction-panic, r=staktrace
Auto merge of #3470 - nical:blob-eviction-panic, r=staktrace

Fix blob leak panic in rawtests

When rawtests are run in debug mode we panic towards the end because some blobs were not manually evicted from the texture cache. Some of the tests were not fully cleaning up after themselves and this commit fixes that.

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