Rename old crash cases to match the current naming scheme.

Will allow for easy import of crash cases from swift-compiler-crashes.

validation-test/compiler_crashers_fixed/01667-swift-parser-parseexprpostfix.swift

@@ -0,0 +1,23 @@
+// RUN: not %target-swift-frontend %s -parse
+
+// Distributed under the terms of the MIT license
+// Test case submitted to project by https://github.com/practicalswift (practicalswift)
+// Test case found by fuzzing
+
+func compose<U) {
+class A {
+protocol a {
+return [Any) -> A {
+}
+case c]
+}
+var b {
+case c]()(t: U : b)!.c: c<U -> {
+}
+self.init() {
+return d(g> String {
+case C(mx : A> Bool {
+}
+}
+}
+ty