Disable targets, where we use Nix packages.

--- a/utils/build-presets.ini
+++ b/utils/build-presets.ini
@@ -818,8 +818,6 @@
 swiftpm
 swift-driver
 xctest
-libicu
-libcxx
 swiftdocc
 
 # build-ninja
@@ -830,9 +828,7 @@
 install-swiftpm
 install-swift-driver
 install-xctest
-install-libicu
 install-prefix=%(install_prefix)s
-install-libcxx
 install-sourcekit-lsp
 install-swiftdocc
 build-swift-static-stdlib