[build] Build Windows x86 version with py3.7

and remove redundant tests
Closes #390

:ci skip

Co-authored by: pukkandan, shirt-dev

.github/workflows/core.yml

@@ -9,11 +9,13 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-18.04]
-        python-version: [3.6, 3.7, 3.8, 3.9, pypy-3.6, pypy-3.7]
+        # py3.9 is in quick-test
+        python-version: [3.7, 3.8, pypy-3.6, pypy-3.7]
         run-tests-ext: [sh]
         include:
+        # atleast one of the tests must be in windows
         - os: windows-latest
-          python-version: 3.4  # Windows x86 build is still in 3.4
+          python-version: 3.6
           run-tests-ext: bat
     steps:
     - uses: actions/checkout@v2