fixed testing harness: made some amends, removed Cross.toml, build-std args in cmdline

Author: sayantn

.github/workflows/common.yml

@@ -1,4 +1,4 @@
-name: common
+name: Check
 
 on:
   push:
@@ -190,4 +190,5 @@ jobs:
     uses: ./.github/workflows/runtest.yml
     with:
       target: ${{ matrix.target }}
-      channel: nightly
+      channel: nightly
+      build-std: true

.github/workflows/runtest.yml

@@ -12,6 +12,10 @@ on:
         required: false
         type: string
         default: ''
+      build-std:
+        required: false
+        type: boolean
+        default: false
 
 jobs:
   test:
@@ -37,7 +41,7 @@ jobs:
         with:
           use-cross: true
           command: build
-          args: --target ${{ inputs.target }} ${{ inputs.channel == 'nightly' && '--features=nightly' || '' }}
+          args: --target ${{ inputs.target }} ${{ inputs.channel == 'nightly' && '--features=nightly' || '' }} ${{ inputs.build-std && '-Z build-std=core' || '' }}
 
       - name: Test
         uses: actions-rs/cargo@v1