Disable @_noLocks annotations when we don't have a host Swift compiler

These annotations require optimization passes that are written in
Swift, so we need a host Swift compiler to properly process them. Use
`hasFeature(Macros)` as a way to gate the annotations.

Author: DougGregor

stdlib/public/core/Availability.swift

@@ -52,7 +52,9 @@ public func _stdlib_isOSVersionAtLeast(
 @_semantics("availability.osversion")
 @_effects(readnone)
 @_unavailableInEmbedded
+#if hasFeature(Macros)
 @_noLocks
+#endif
 public func _stdlib_isOSVersionAtLeast(
   _ major: Builtin.Word,
   _ minor: Builtin.Word,
@@ -65,7 +67,9 @@ public func _stdlib_isOSVersionAtLeast(
 @_semantics("availability.osversion")
 @_effects(readnone)
 @_alwaysEmitIntoClient
+#if hasFeature(Macros)
 @_noLocks
+#endif
 public func _stdlib_isOSVersionAtLeast_AEIC(
   _ major: Builtin.Word,
   _ minor: Builtin.Word,
@@ -110,7 +114,9 @@ public func _stdlib_isOSVersionAtLeast_AEIC(
 @_semantics("availability.osversion")
 @_effects(readnone)
 @available(macOS 10.15, iOS 13.0, *)
+#if hasFeature(Macros)
 @_noLocks
+#endif
 public func _stdlib_isVariantOSVersionAtLeast(
   _ major: Builtin.Word,
   _ minor: Builtin.Word,
@@ -153,7 +159,9 @@ public func _stdlib_isVariantOSVersionAtLeast(
 @_semantics("availability.osversion")
 @_effects(readnone)
 @_unavailableInEmbedded
+#if hasFeature(Macros)
 @_noLocks
+#endif
 public func _stdlib_isOSVersionAtLeastOrVariantVersionAtLeast(
   _ major: Builtin.Word,
   _ minor: Builtin.Word,