Added a second batch of coverage tests found by GraphicsFuzz

Added a second batch of coverage tests found by GraphicsFuzz

New tests:

dEQP-VK.graphicsfuzz.cov-basic-block-discard-in-function
dEQP-VK.graphicsfuzz.cov-const-folding-clamp-inside-while
dEQP-VK.graphicsfuzz.cov-const-folding-clamp-vs-original
dEQP-VK.graphicsfuzz.cov-const-folding-min-as-loop-range
dEQP-VK.graphicsfuzz.cov-constant-folding-atan-over-tanh
dEQP-VK.graphicsfuzz.cov-dead-branch-func-return-arg
dEQP-VK.graphicsfuzz.cov-fold-and-in-for-loop-range
dEQP-VK.graphicsfuzz.cov-folding-clamp-cmp-const-first
dEQP-VK.graphicsfuzz.cov-folding-rules-merge-div-mul
dEQP-VK.graphicsfuzz.cov-folding-rules-merge-divs
dEQP-VK.graphicsfuzz.cov-folding-rules-merge-mul-div
dEQP-VK.graphicsfuzz.cov-folding-rules-negate-div
dEQP-VK.graphicsfuzz.cov-inline-pass-return-in-loop
dEQP-VK.graphicsfuzz.cov-machinevaluetype-one-iter-loop
dEQP-VK.graphicsfuzz.cov-vector-log2-cosh

Components: Vulkan
Change-Id: Ifcb87053f5ff52ee5b0f7460f289e3e144e31a1a