Add a couple of regression tests

Author: slavapestov

validation-test/compiler_crashers_2_fixed/0183-sr8998.swift

@@ -0,0 +1,15 @@
+// RUN: not %target-swift-frontend -emit-ir %s
+
+protocol P {
+    associatedtype A: Q where A.B == Self
+}
+
+protocol Q {
+    associatedtype B: P where B.A == Self
+}
+
+struct S1<T>: P where T: Q { }
+
+struct S2: Q {
+    typealias B = S1<S2>
+}

validation-test/compiler_crashers_2_fixed/0184-8764.swift

@@ -0,0 +1,12 @@
+// RUN: %target-swift-frontend -emit-ir %s
+
+@discardableResult public func applyWrapped<T, U>(function: Optional<(T) -> U>, to value: Optional<T>) -> Optional<U> {
+    switch (function, value) {
+    case (let .some(f), let .some(v)):
+        return .some(f(v))
+    case (.none, _):
+        return .none
+    case (_, .none):
+        return .none
+    }
+}