Introduces `__builtin_hlsl_buffer_update_counter` clang buildin that is used to implement IncrementCounter and DecrementCounter methods on RWStructuredBuffer and RasterizerOrderedStructuredBuffer. The builtin is translated to LLVM intrisics llvm.dx.bufferUpdateCounter/llvm.spv.bufferUpdateCounter.

Introduces `BuiltinTypeMethodBuilder` helper in `HLSLExternalSemaSource` that allows adding methods to builtin types
using the builder pattern like this:

   BuiltinTypeMethodBuilder(Sema, RecordBuilder, "MethodName", ReturnType)
       .addParam("param_name", Type, InOutModifier)
       .callBuiltin("buildin_name", { BuiltinParams })
       .finalizeMethod();

Fixes llvm#113513

…der, fix generated CallExpr type

…counter

Do not complete definition if we already got one from precompiled headers.

…counter

…update tests