Fix slice/exec_ctx interactions

Ruby Advanced Interop Server Side

Fixing submodules sanity.

Faster test building: avoid repeated linking

Bazel integration

Fixes for tests

Fixes for tests

Remove old fixture

Changes to exec_ctx/closure/combiner/workqueue interfaces

attach trailing metadata to ruby bidi call op when it's received

change ruby default unimplemented ruby server handler to have two aguments

remove test of exception on ruby thread pool overload

Revert "Revert "Reduce memory bloat (each server cq is very expensive)""

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