[SPIR-V] Add GetDimensions() method for vk::SampledTexture2D type.

[luciechoi]

Part of #7979

Implement methods for vk::SampledTexture2D:

void GetDimensions(uint mipLevel, uint width, uint height, uint numLevels)
void GetDimensions(uint width, uint height)
void GetDimensions(uint mipLevel, float width, float height, float numLevels)
void GetDimensions(float width, float height)
void GetDimensions(uint mipLevel, int width, int height, int numLevels)
void GetDimensions(int width, int height)

Please see the last commit