SILOptimizer: Disable invalid passes in C++-only compiler

[etcwilde]

The SimplifyCFG and LoopRotate passes result in verification failures when built in a compiler that is not built with Swift sources enabled.

Fixes: rdar://146357242

[etcwilde]

@swift-ci please test

[etcwilde]

@swift-ci please test

[etcwilde]

@swift-ci please test

[3405691582]

FYI: this seems to cause a compiler crash when bootstrapping (with Concurrency enabled) trying to compile Deque+Storage.swift. Retaining the SimplifyCFG pass avoids the crash.

Stackdump fragment:

1.      Swift version 6.2-dev (LLVM b1e56f1b39b82cd, Swift bca1378fdbf1c58)     
2.      Compiling with effective version 5.10                                   
3.      While evaluating request ExecuteSILPipelineRequest(Run pipelines {      
PrepareOptimizationPasses, EarlyModulePasses, HighLevel,Function+EarlyLoopOpt, H
ighLevel,Module+StackPromote, MidLevel,Function, ClosureSpecialize, LowLevel,Fun
ction, LateLoopOpt, SIL Debug Info Generator } on SIL for _Concurrency)         
4.      While running pass #496334 SILFunctionTransform "CodeSinking" on SI     
LFunction "@$ss6_DequeV8_StorageV13_growCapacity2to8linearlyS2i_SbtFyt_Tg5".    
 for '_growCapacity(to:linearly:)' ...