Merge pull request #697 from practicalswift/sourcekit-052-swift-mangle-mangler-manglegenericsignatureparts

[SourceKit] Add test case for crash triggered in swift::Mangle::Mangler::mangleGenericSignatureParts(…)

Author: gribozavr

validation-test/IDE/crashers/052-swift-mangle-mangler-manglegenericsignatureparts.swift

@@ -0,0 +1,7 @@
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// REQUIRES: asserts
+var b{class d<A{
+func a{struct S<T
+{func a{
+func b<i{let h:St
+class a{var _=#^A^#