Fix invalid CFG in SPIR-V 1.4 tests

Fix invalid CFG in SPIR-V 1.4 tests

VK-GL-CTS Issue: 2122

Component: Vulkan

Affected tests:
dEQP-VK.spirv_assembly.instruction.spirv1p4.opptrdiff.variable_pointers_vars_ssbo_2_diff
dEQP-VK.spirv_assembly.instruction.spirv1p4.opptrequal.variable_pointers_ssbo_2_equal
dEQP-VK.spirv_assembly.instruction.spirv1p4.opptrnotequal.variable_pointers_ssbo_2_not_equal
dEQP-VK.spirv_assembly.instruction.spirv1p4.nonwritable.function_nonwritable
dEQP-VK.spirv_assembly.instruction.spirv1p4.nonwritable.private_nonwritable

Change-Id: Ie886aba331a7721d3d3468dd8c616ca7ab2d5664