[Preset] Update the foundation preset to use mixin from swift Linux preset

(cherry picked from commit 42346ac)

Author: shahmishal

utils/build-presets.ini

@@ -1697,30 +1697,10 @@ install-swift
 #===------------------------------------------------------------------------===#
 # Linux corelibs foundation preset
 #===------------------------------------------------------------------------===#
-[preset: buildbot_corelibs_foundation_linux,debug]
-release
-validation-test
+[preset: buildbot_linux,foundation=debug]
+mixin-preset=buildbot_linux
 
-libicu
-llbuild
-swiftpm
-xctest
 debug-foundation
-libdispatch
 
-reconfigure
-lit-args=-v
-
-[preset: buildbot_corelibs_foundation_linux,release]
-release
-validation-test
-
-libicu
-llbuild
-swiftpm
-xctest
-foundation
-libdispatch
-
-reconfigure
-lit-args=-v
+[preset: buildbot_linux,foundation=release]
+mixin-preset=buildbot_linux