clangd-tsan-ubuntu: only build clangd{,-indexer,-index-server}

Differential Revision: https://reviews.llvm.org/D91597
diff --git a/buildbot/osuosl/master/config/builders.py b/buildbot/osuosl/master/config/builders.py
index 9e65ee6..3e681e2 100644
--- a/buildbot/osuosl/master/config/builders.py
+++ b/buildbot/osuosl/master/config/builders.py
@@ -1893,6 +1893,7 @@
          clean=True,
          depends_on_projects=["llvm", "clang", "clang-tools-extra"],
          checks=["check-clangd"],
+         targets=["clangd", "clangd-index-server", "clangd-indexer"],
          extra_configure_args=[
              "-DLLVM_CCACHE_BUILD=ON",
              "-DLLVM_USE_SANITIZER=Thread",