Add module trace information for strict memory safety

Extend the module trace format with a field indicating whether a given
module, or any module it depends on, was compiled with strict memory
safety enabled. This separate output from the compiler can be used as
part of an audit to determine what parts of Swift programs are built
with strict memory safety checking enabled.

lib/AST/Module.cpp

@@ -781,6 +781,7 @@ ModuleDecl::ModuleDecl(Identifier name, ASTContext &ctx,
   Bits.ModuleDecl.CXXStdlibKind = 0;
   Bits.ModuleDecl.AllowNonResilientAccess = 0;
   Bits.ModuleDecl.SerializePackageEnabled = 0;
+  Bits.ModuleDecl.StrictMemorySafety = 0;
 
   // Populate the module's files.
   SmallVector<FileUnit *, 2> files;