[embedded] Tweak REQUIRES clauses in linkage tests

Author: kubamracek

test/embedded/linkage-custom-entry-point.swift

@@ -2,7 +2,6 @@
 // RUN: %target-swift-frontend %s -module-name Application -parse-as-library -entry-point-function-name Application_main -mergeable-symbols -O -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: OS=macosx || OS=linux-gnu
 // REQUIRES: swift_feature_Embedded
 
 @main

test/embedded/linkage-mergeable-dead-strip.swift

@@ -8,8 +8,8 @@
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: executable_test
-// REQUIRES: OS=macosx
 // REQUIRES: swift_feature_Embedded
+// REQUIRES: swift_feature_SymbolLinkageMarkers
 
 public func a_this_is_unused() { }
 

test/embedded/linkage-mergeable.swift

@@ -8,7 +8,6 @@
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: executable_test
-// REQUIRES: OS=macosx || OS=linux-gnu
 // REQUIRES: swift_feature_Embedded
 
 // BEGIN MyModule.swift

test/embedded/linkage-mergeable2.swift

@@ -8,7 +8,6 @@
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: executable_test
-// REQUIRES: OS=macosx || OS=linux-gnu
 // REQUIRES: swift_feature_Embedded
 
 // BEGIN MyModule.swift

test/embedded/linkage-public-exports.swift

@@ -2,7 +2,6 @@
 // RUN: %target-swift-frontend %s -mergeable-symbols -O -enable-experimental-feature Embedded -emit-ir | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
-// REQUIRES: OS=macosx || OS=linux-gnu
 // REQUIRES: swift_feature_Embedded
 
 public func foo1() { }