[build-script] Update presets to reflect that SwiftSyntax now contains all generated files

We no longer need to generate the files using gyb. Instead we should
check that the generated files are actually up-to-date.

Author: ahoppen

utils/build-presets.ini

@@ -1125,6 +1125,10 @@ libcxx
 indexstore-db
 sourcekit-lsp
 
+# Don't generate the SwiftSyntax gyb files. Instead verify that up-to-date ones
+# are checked in.
+swiftsyntax-verify-generated-files
+
 # Build with debug info, this allows us to symbolicate crashes from
 # production builds.
 release-debuginfo
@@ -1360,6 +1364,10 @@ llbuild
 swiftpm
 swiftsyntax
 
+# Don't generate the SwiftSyntax gyb files. Instead verify that up-to-date ones
+# are checked in.
+swiftsyntax-verify-generated-files
+
 # Build sourcekit-lsp & indexstore-db
 indexstore-db
 sourcekit-lsp