Vulkan: Fix flakiness in MultipleProgramsShareDescriptors Precision differences causes the test to be flaky on some vendors. The test is not validating color accuracy, there is no need to use random numbers. Bug: angleproject:42265270 Change-Id: Ied8794d14b394e049e5735d4c42a7baf6e3aca0f Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6129616 Commit-Queue: mohan maiya <m.maiya@samsung.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Yuxin Hu <yuxinhu@google.com>