presets: Update swift macos/linux preset

Update the Swift repo build preset to depend on the
mixin_swiftpm_base preset to ensure it has all the
same presets as SwiftPM.

Author: bkhouri

utils/build-presets.ini

@@ -609,6 +609,7 @@ mixin-preset=
     buildbot_incremental_base
     lldb-smoketest,tools=RA
     mixin_buildbot_install_components_with_clang
+    mixin_swiftpm_base
 build-subdir=buildbot_incremental
 
 # We build release+asserts.
@@ -1077,6 +1078,7 @@ mixin-preset=
 mixin-preset=
     mixin_lightweight_assertions,no-stdlib-asserts
     mixin_linux_installation
+    mixin_swiftpm_base
 build-subdir=buildbot_linux
 lldb
 release