[SPIRV] Update submodules (#6936)

Updates the submodules. One test started to fail because the
"needslegalization" flag was not set correctly. That was fixed by
identifiying SubpassInput as an opaque type.

external/SPIRV-Headers

@@ -1 +1 @@
-Subproject commit 2a9b6f951c7d6b04b6c21fe1bf3f475b68b84801
+Subproject commit ec59c77a3bb5c747a369931ef101ac7c14823f2f

external/SPIRV-Tools

@@ -1 +1 @@
-Subproject commit 6dcc7e350a0b9871a825414d42329e44b0eb8109
+Subproject commit 44936c4a9d42f1c67e34babb5792adf5bce7f76b

tools/clang/lib/SPIRV/AstTypeProbe.cpp

@@ -1098,6 +1098,9 @@ bool isOpaqueType(QualType type) {
 
     if (name == "RayQuery")
       return true;
+
+    if (name == "SubpassInput")
+      return true;
   }
   return false;
 }