[build-script] When only building llvm incrementally on linux, do not even try to build llbuild/swiftpm/xctest/foundation.

Author: gottesmm

utils/build-presets.ini

@@ -667,18 +667,25 @@ install-destdir=%(install_destdir)s
 # Path to the .tar.gz package we would create.
 installable-package=%(installable_package)s
 
-
-[preset: buildbot_incremental_linux]
+[preset: buildbot_incremental_linux_base]
+assertions
 release
 test
 validation-test
+
+dash-dash
+
+reconfigure
+
+[preset: buildbot_incremental_linux]
+mixin-preset=buildbot_incremental_linux_base
+build-subdir=buildbot_incremental
+
 llbuild
 swiftpm
 xctest
 foundation
-
 dash-dash
-reconfigure
 
 [preset: buildbot_incremental_linux,long_test]
 mixin-preset=buildbot_incremental_linux
@@ -689,8 +696,8 @@ long-test=1
 test-optimized=0
 
 [preset: buildbot_incremental_linux,llvm-only]
-mixin-preset=buildbot_incremental_linux
-build-subdir=buildbot_incremental_linux_llvmonly
+mixin-preset=buildbot_incremental_linux_base
+build-subdir=buildbot_incremental_llvmonly
 
 dash-dash