[stdlib] Remove unnecessary type annotations in hashValue

Author: xwu

stdlib/public/core/Arrays.swift.gyb

@@ -2303,7 +2303,7 @@ extension ${Self} : Hashable where Element : Hashable {
   @available(swift, introduced: 4.1)
   public var hashValue: Int {
     // FIXME(ABI)#177: <rdar://problem/18915294> Issue applies to Array too
-    var result: Int = 0
+    var result = 0
     for element in self {
       result = _combineHashValues(result, element.hashValue)
     }

stdlib/public/core/Dictionary.swift

@@ -1452,7 +1452,7 @@ extension Dictionary: Hashable where Value: Hashable {
   @available(swift, introduced: 4.1)
   public var hashValue: Int {
     // FIXME(ABI)#177: <rdar://problem/18915294> Issue applies to Dictionary too
-    var result: Int = 0
+    var result = 0
     for (k, v) in self {
       let combined = _combineHashValues(k.hashValue, v.hashValue)
       result ^= _mixInt(combined)

stdlib/public/core/ExistentialCollection.swift.gyb

@@ -1264,7 +1264,7 @@ extension AnyCollection : Hashable where Element : Hashable {
   @available(swift, introduced: 4.1)
   public var hashValue: Int {
     // FIXME(ABI)#177: <rdar://problem/18915294> Issue applies to AnyCollection too
-    var result: Int = 0
+    var result = 0
     for element in self {
       result = _combineHashValues(result, element.hashValue)
     }

stdlib/public/core/Mirror.swift

@@ -781,7 +781,7 @@ extension DictionaryLiteral: Hashable where Key: Hashable, Value: Hashable {
   @available(swift, introduced: 4.1)
   public var hashValue: Int {
     // FIXME(ABI)#177: <rdar://problem/18915294> Issue applies to DictionaryLiteral too
-    var result: Int = 0
+    var result = 0
     for element in self {
       let elementHashValue =
         _combineHashValues(element.key.hashValue, element.value.hashValue)