Fix an issue of spirv_type used in local variable definitions

We previously use createOp() in SPV builder to create type declaration.
However, all type declarations should be placed in const-type-variable
declaration section. And duplicated type defintions ought to be avoided.
We now make a method in SPV builder to perform this operation with a
more general solution: makeGenericType().

gtests/Spv.FromFile.cpp

@@ -373,6 +373,7 @@ INSTANTIATE_TEST_SUITE_P(
         "spv.intrinsicsSpirvLiteral.vert",
         "spv.intrinsicsSpirvStorageClass.rchit",
         "spv.intrinsicsSpirvType.rgen",
+        "spv.intrinsicsSpirvTypeLocalVar.vert",
         "spv.invariantAll.vert",
         "spv.layer.tese",
         "spv.layoutNested.vert",