Reduces the amount of LLVM IR produced when the limits are compile-time known.

Reduces full test execution time of dEQP-VK.ubo.random.all_out_of_order_offsets.45 by about half.

For dEQP-VK.ubo.random.all_shared_buffer.48:
• Reduces number of pre-opt LLVM IR instructions by about 40%.
• Reduces full test execution time by about 30%

Bug: b/135609394
Change-Id: I3c46d56910bb8373a355ab8d570d3093944afc84
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/33053Reviewed-by: Chris Forbes <chrisforbes@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Ben Clayton <bclayton@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>