[SYCL][CMake] Enable LLVM_LINK_LLVM_DYLIB builds of the SYCL toolchain

[koparasy]

Enable building the SYCL toolchain with -DLLVM_LINK_LLVM_DYLIB=ON
(-DCLANG_LINK_CLANG_DYLIB=ON), previously unsupported.

This is a needed change to allow clang plugins to be loaded during compilation
of sycl code.

Under dylib, tools link libLLVM.so instead of the LLVM component
libraries and so don't inherit their INTERFACE properties. Fixes:

• Bump the vc-intrinsics pin to 0c3296b, which drops a spurious
  LLVMSPIRVLib dependency on LLVMGenXIntrinsics that formed an illegal
  cross-dylib cycle (LLVM -> SYCLLowerIR -> GenXIntrinsics -> SPIRVLib
  -> LLVM) and broke CMake configuration.
• LLVMSPIRVLib is not part of libLLVM.so: link it explicitly in
  spirv-to-ir-wrapper and sycl-jit (matching llvm-spirv).
• sycl-post-link and sycl-jit include vc-intrinsics headers; add the
  LLVMGenXIntrinsics INTERFACE include directories explicitly.

All changes are guarded by LLVM_LINK_LLVM_DYLIB; static builds are
unchanged.

[koparasy]

@vmustya for your verifier.