Remove virtual type support hint

[temaEmelyan]

Please make sure you consider the following:

• Add tests that use __typename in queries
• Does this change work with all nadel transformations (rename, type rename, hydration, etc)? Add tests for this.
• Is it worth using hints for this change in order to be able to enable a percentage rollout?
• Do we need to add integration tests for this change in the graphql gateway?
• Do we need a pollinator check for this?

[github-actions]

Test Results

  657 files   - 1    657 suites   - 1   1m 9s ⏱️ -3s
2 209 tests  - 2  1 651 ✅ ±0  558 💤  - 1  0 ❌  - 1 
2 217 runs   - 2  1 659 ✅ ±0  558 💤  - 1  0 ❌  - 1 

Results for commit a41e098. ± Comparison against base commit 6553955.

This pull request removes 2 tests.

graphql.nadel.tests.next.fixtures.hydration.statics.StaticHydrationVirtualTypeHintOffTest ‑ execute()
graphql.nadel.tests.next.fixtures.hydration.statics.StaticHydrationVirtualTypeHintOffTest ‑ executeNoDefer()

♻️ This comment has been updated with latest results.