tests: fix lifetimes of objects in two tests

Those tests rely on lexical object lifetimes. But lifetimes are only guaranteed for "variables" but not for temporary objects.
Storing those objects in variables fixes the issue.

This fixes the tests when running them in optimize mode and when OSSA modules are enabled.

This is part of rdar://140229560.

Author: eeckstein

test/Interpreter/lifetime_nonmutating_address_only.swift

@@ -23,4 +23,10 @@ extension SomeProtocol {
     }
 }
 
-SomeClass().someProperty.x = 32
+func testit() {
+  let c = SomeClass()
+  c.someProperty.x = 32
+}
+
+testit()
+

validation-test/stdlib/ErrorHandling.swift

@@ -303,7 +303,10 @@ ErrorHandlingTests.test("ErrorHandling/Sequence filter") {
   let initialCount = NoisyCount
   for condition in [true, false] {
     for throwAtCount in 0...3 {
-      let sequence = [Noisy(), Noisy(), Noisy()]
+      let n1 = Noisy()
+      let n2 = Noisy()
+      let n3 = Noisy()
+      let sequence = [n1, n2, n3]
       var loopCount = 0
       do {
         let result: [Noisy] = try sequence.filter { _ in