[build] Enable swift parser integration in linux lldb preset

swift-backtrace currently doens't build property 'bootstrapping' mode.
Although we should fix the 'bootstrapping' issue separately, since lldb
should be built with parser integration, enable it.

rdar://116470411
(cherry picked from commit 684d963)

Author: rintaro

utils/build-presets.ini

@@ -2905,7 +2905,6 @@ skip-test-swift
 skip-build-benchmarks
 skip-test-foundation
 
-# Temporarily disable early swift driver/syntax builds so that linux images
+# Temporarily disable early swift driver builds so that linux images
 # can use the swift release images as a base.
 skip-early-swift-driver
-skip-early-swiftsyntax