[cmake] Propagate lit_jobs to LLVM_LIT_ARGS

Missed this when I originally added the
`--lit-jobs` build-script option, propagate the value
provided to `LLVM_LIT_ARGS` in addition to
`SWIFT_LIT_ARGS`.

Author: hamishknight

utils/swift_build_support/swift_build_support/products/cmake_product.py

@@ -408,9 +408,9 @@ def host_cmake_options(self, host_target):
         swift_cmake_options.define('SWIFT_HOST_VARIANT_ARCH', swift_host_variant_arch)
 
         llvm_cmake_options.define('LLVM_LIT_ARGS', '{} -j {}'.format(
-            self.args.lit_args, self.args.build_jobs))
+            self.args.lit_args, self.args.lit_jobs))
         swift_cmake_options.define('LLVM_LIT_ARGS', '{} -j {}'.format(
-            self.args.lit_args, self.args.build_jobs))
+            self.args.lit_args, self.args.lit_jobs))
 
         if self.args.clang_profile_instr_use:
             llvm_cmake_options.define('LLVM_PROFDATA_FILE',