Delete redundant constraints in NSData.swift causing warnings

[e78l]

Delete 2 constraints causing warnings in NSData.swift introduced from swiftlang/swift@ddc2775

Compiler warnings suggest redundant last 2 constraints are implied by Collection:

Foundation/NSData.swift:590:253: warning: redundant same-type constraint 'T.Iterator.Element' == 'T.SubSequence.Iterator.Element'
    private static func searchSubSequence<T : Collection, T2 : Sequence>(_ subSequence : T2, inSequence seq: T,anchored : Bool) -> T.Index? where T.Iterator.Element : Equatable, T.Iterator.Element == T2.Iterator.Element, T.SubSequence.Iterator.Element == T.Iterator.Element, T.Indices.Iterator.Element == T.Index {
                                                                                                                                                                                                                                                            ^
Foundation/NSData.swift:590:47: note: previous same-type constraint 'T._Element' == 'T.Iterator.Element' implied here
    private static func searchSubSequence<T : Collection, T2 : Sequence>(_ subSequence : T2, inSequence seq: T,anchored : Bool) -> T.Index? where T.Iterator.Element : Equatable, T.Iterator.Element == T2.Iterator.Element, T.SubSequence.Iterator.Element == T.Iterator.Element, T.Indices.Iterator.Element == T.Index {
                                              ^
Foundation/NSData.swift:590:303: warning: redundant same-type constraint 'T.Index' == 'T.Indices.Iterator.Element'
    private static func searchSubSequence<T : Collection, T2 : Sequence>(_ subSequence : T2, inSequence seq: T,anchored : Bool) -> T.Index? where T.Iterator.Element : Equatable, T.Iterator.Element == T2.Iterator.Element, T.SubSequence.Iterator.Element == T.Iterator.Element, T.Indices.Iterator.Element == T.Index {
                                                                                                                                                                                                                                                                                                              ^
Foundation/NSData.swift:590:47: note: previous same-type constraint 'T.Index' == 'T.Indices.Index' implied here
    private static func searchSubSequence<T : Collection, T2 : Sequence>(_ subSequence : T2, inSequence seq: T,anchored : Bool) -> T.Index? where T.Iterator.Element : Equatable, T.Iterator.Element == T2.Iterator.Element, T.SubSequence.Iterator.Element == T.Iterator.Element, T.Indices.Iterator.Element == T.Index {

[pushkarnk]

Looks good to me. Thanks.
@swift-ci test and merge

[pushkarnk]

@swift-ci test and merge