Add support for '--config=clang-tidy' (#3559)

This sets things up to use `bazel` to run `clang-tidy` using
https://github.com/erenon/bazel_clang_tidy.

I'm fixing issues outside of explorer, and disabling clang-tidy for
targets in explorer that have legacy issues. I was going to disable
clang-tidy for targets in explorer such as interpreter anyways, because
they're slow to parse, and just extended that to the currently failing
targets.

toolchain/lex/tokenized_buffer_benchmark.cpp

@@ -854,6 +854,7 @@ constexpr DispatchTableT DispatchTable = []() {
   for (int i = 0; i < 256; ++i) {
     tmp_table[i] = &BasicDispatch<DispatchTable<NumDispatchTargets>>;
   }
+  // NOLINTNEXTLINE(readability-braces-around-statements): False positive.
   if constexpr (NumDispatchTargets > 1) {
     // Add additional dispatch targets from our specializable array.
     SpecializeDispatchTable<DispatchTable<NumDispatchTargets>>(