sw::Intermediate would only clear the contents to zero in debug builds, but would always validate that these were nullptr in release (ASSERT still warns in release).
Given the cost nullifying this memory is negligable in comparison to the actual LLVM JIT, always clear.

Changed a bunch of ASSERT()s to ASSERT_MSG() where the additional information is useful.

Replaced a few remaining calls to assert() with ASSERT()

Bug: b/127433389
Change-Id: Ifac89ca061bf7d61ff7d0de1792eeda18fad275c
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/27568
Presubmit-Ready: Ben Clayton <bclayton@google.com>
Tested-by: Ben Clayton <headlessclayton@gmail.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>