[clangd] Disable support for clang-tidy suppression blocks (NOLINTBEGIN)

[sammccall]

Summary

The implementation is very inefficient and we pay the cost even when the feature is not used

[kadircet]

I am a little worried about the discrepancy we'll get here, but (un)fortunately it won't be the first with clang-tidy.

Also gave the author a headsup in https://reviews.llvm.org/D108560#3192081, looks like they're already working on some improvements. Let's hope that we can have this landed with LLVM-14 otherwise I think we should also document this in https://clangd.llvm.org/features#clang-tidy-checks.

[shraiysh]

Hey folks, this commit seems to cause multiple buildbot failures 1 2 3. Can someone please revert this change while it gets fixed? Thanks!

clang-tools-extra/clangd/ParsedAST.cpp

ASTDiags.setLevelAdjuster([&](DiagnosticsEngine::Level DiagLevel,
           // to match clang-tidy's behaviour.
           bool IsInsideMainFile =
               Info.hasSourceManager() &&
               isInsideMainFile(Info.getLocation(), Info.getSourceManager());
           SmallVector<tidy::ClangTidyError, 1> TidySuppressedErrors;
           if (IsInsideMainFile &&
               tidy::shouldSuppressDiagnostic(DiagLevel, Info, *CTContext,
                                              TidySuppressedErrors,
-                                             /*AllowIO=*/false)) {
+                                             /*AllowIO=*/false,
+                                             /*EnableNolintBlocks=*/false)) {
             // FIXME: should we expose the suppression error (invalid use of
             // NOLINT comments)?
             return DiagnosticsEngine::Ignored;
           }
 
           // Check for warning-as-error.
           if (DiagLevel == DiagnosticsEngine::Warning &&
               CTContext->treatAsError(CheckName)) {