[test] Remove some REQUIRES: for features not longer used in those files

While doing #76740 I iteratively was adding new `REQUIRES:` as new
usages of the features were found, but I did not realize that at the
same time other people might be removing some of those usages. The tests
in this commit had some `REQUIRES:` line for a previous
`-enable-experimental/upcoming-feature`, but they not longer use those
features, so the `REQUIRES:` were effectively disabling the tests (at
least in the case of `KeyPathWithStaticMembers`. In other cases they
might still had executed).

test/Concurrency/isolated_default_arguments.swift

@@ -4,8 +4,6 @@
 
 // REQUIRES: concurrency
 // REQUIRES: swift_feature_InferSendableFromCaptures
-// REQUIRES: swift_feature_IsolatedDefaultValues
-// REQUIRES: swift_feature_RegionBasedIsolation
 
 @globalActor
 actor SomeGlobalActor {

test/Concurrency/nonisolated_rules.swift

@@ -1,7 +1,6 @@
 // RUN: %target-swift-frontend -target %target-swift-5.1-abi-triple -swift-version 6 -parse-as-library %s -emit-sil -o /dev/null -verify -strict-concurrency=complete
 
 // REQUIRES: concurrency
-// REQUIRES: swift_feature_GlobalActorInferenceCutoff
 
 @MainActor
 protocol GloballyIsolated {}

test/Interpreter/keypath.swift

@@ -1,7 +1,6 @@
 // RUN: %target-run-simple-swift | %FileCheck %s
 
 // REQUIRES: executable_test
-// REQUIRES: swift_feature_KeyPathWithStaticMembers
 
 // UNSUPPORTED: use_os_stdlib
 // UNSUPPORTED: back_deployment_runtime

test/Interpreter/static_keypaths.swift

@@ -20,7 +20,6 @@
 
 // REQUIRES: executable_test
 // REQUIRES: OS=macosx
-// REQUIRES: swift_feature_KeyPathWithStaticMembers
 
 // UNSUPPORTED: use_os_stdlib
 // UNSUPPORTED: back_deployment_runtime

test/SILGen/keypaths.swift

@@ -1,8 +1,6 @@
 // RUN: %target-swift-emit-silgen -target %target-swift-5.1-abi-triple -disable-experimental-parser-round-trip -parse-stdlib -module-name keypaths %s | %FileCheck %s
 // FIXME: Remove '-disable-experimental-parser-round-trip'.
 
-// REQUIRES: swift_feature_KeyPathWithStaticMembers
-
 
 import Swift
 

test/SILOptimizer/access_wmo_diagnose.swift

@@ -1,7 +1,5 @@
 // RUN: %target-swift-frontend -parse-as-library -emit-sil -enforce-exclusivity=checked -primary-file %s -o /dev/null -verify
 
-// REQUIRES: swift_feature_KeyPathWithStaticMembers
-
 // AccessEnforcementWMO assumes that the only way to address a global or static
 // property is via a formal begin_access. If we ever allow keypaths for static
 // properties, which I think is conceivable, then this test will fail to produce

test/SymbolGraph/Symbols/Mixins/DeclarationFragments/Full/Macros.swift

@@ -1,5 +1,4 @@
 // REQUIRES: swift_swift_parser
-// REQUIRES: swift_feature_Macros
 
 // RUN: %empty-directory(%t)
 // RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -module-name=MacroDefinition %S/Inputs/stringify_macro.swift -g -no-toolchain-stdlib-rpath -swift-version 5

test/attr/attr_dynamic_member_lookup.swift

@@ -1,7 +1,5 @@
 // RUN: %target-typecheck-verify-swift
 
-// REQUIRES: swift_feature_KeyPathWithStaticMembers
-
 var global = 42
 
 @dynamicMemberLookup

test/expr/unary/keypath/keypath.swift

@@ -1,7 +1,5 @@
 // RUN: %target-swift-frontend -typecheck -parse-as-library %s -verify
 
-// REQUIRES: swift_feature_KeyPathWithStaticMembers
-
 struct Sub: Hashable {
   static func ==(_: Sub, _: Sub) -> Bool { return true }
   func hash(into hasher: inout Hasher) {}