Fix some validation-test regressions, mostly by tweaking tests

but also by being a little more defensive during recovery.

Swift SVN r30424

lib/Sema/CSDiag.cpp

@@ -2565,8 +2565,10 @@ FailureDiagnosis::collectCalleeCandidateInfo(Expr *fn, Type actualArgsType,
 }
 
 bool FailureDiagnosis::visitBinaryExpr(BinaryExpr *binop) {
+  // Pre-checking can turn (T,U) into a TypeExpr.  That doesn't happen
+  // except in independent type-checking like this, so just ignore it.
   auto argExpr =
-    cast_or_null<TupleExpr>(typeCheckChildIndependently(binop->getArg()));
+    dyn_cast_or_null<TupleExpr>(typeCheckChildIndependently(binop->getArg()));
   if (!argExpr) return true;
 
   auto argTuple = argExpr->getType()->getAs<TupleType>();

validation-test/compiler_crashers_2_fixed/0030-rdar19534837.swift

@@ -1,4 +1,4 @@
-// RUN: not %target-swift-frontend %s -parse
+// RUN: %target-swift-frontend %s -parse
 
 _ = {
   typealias A = Int

validation-test/compiler_crashers_fixed/0045-swift-lowering-adjustfunctiontype.swift

@@ -5,5 +5,5 @@
 // http://www.openradar.me/17317691
 
 func f() {
-    ({}) // expected-error {{type of expression is ambiguous without more context}}
+    ({}) // expected-error {{expression resolves to an unused function}}
 }

validation-test/compiler_crashers_fixed/0049-swift-nominaltypedecl-getmembers.swift

@@ -7,5 +7,5 @@ var f = 1
 var e: Int -> Int = {
     return $0
 }
-let d: Int =  { c, b in
-}(f, e) // expected-error {{missing return in a closure expected to return 'Int'}}
+let d: Int =  { c, b in // expected-error {{'()' is not convertible to 'Int'}}
+}(f, e)