Disable irrelevant clang-tidy checks

Previously, the clang-tidy configuration enables all checks and then
disables a few undesired ones. This enables a lot of checks that are
specific to certain kinds of code and aren't relevant for this project.
For example, I noticed several errors from checks specific to LLVM libc.
It makes more sense to enable only the checks that we want instead of
enabling everything and then disabling the checks that we don't want.

.clang-tidy

@@ -1,5 +1,5 @@
 ---
-Checks:          '*,readability-*,-google-runtime-references,-modernize-use-trailing-return-type,-hicpp-signed-bitwise,-fuchsia*,-modernize-use-nodiscard'
+Checks:          'bugprone-*,cert-*,concurrency-*,cppcoreguidelines-*,misc-*,modernize-*,-modernize-use-trailing-return-type,-modernize-use-nodiscard,performance-*,portability-*,readability-*'
 WarningsAsErrors: ''
 HeaderFilterRegex: ''
 AnalyzeTemporaryDtors: false