Remove Vulkan project from Visual Studio solution

CMake (without or without Visual Studio 2019) should be used instead
for the Vulkan build.

Bug: b/139189696
Change-Id: Ib87e34e2a210944446b8ea7bd57504acc4bc98d7
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/37068
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
diff --git a/.gitignore b/.gitignore
index bdd8dfc..b2843d1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,13 +12,9 @@
 .vscode/launch.json
 .vscode/settings.json
 
-# The /build/ directory is recommended for CMake build output and should be
-# ignored, except for Visual Studio project files that we check into the
-# repository and regenerate with build/cmake.sh
+# The /build/ directory is recommended for CMake build output
 !/build
 /build/*
-!/build/cmake.sh
-!/build/Visual Studio 15 2017 Win64/
 
 # Boost is downloaded and extracted to /third_party
 /third_party/boost*