Let `StableHloQuantizationPattern` inherit `OpRewritePattern` instead of `RewritePattern`.
Let `StableHloQuantizationPattern` inherit `OpRewritePattern` instead of `RewritePattern`.

`StableHloQuantizationPattern` is showing the same behavior as `OpRewritePattern<RootOpT>`.

Also includes minor cleanup of removing `llvm::` prefixes when possible.
