Revert "Add 'stdin' argument to command/shell modules"

This reverts commit 393909d0cc.
Reverte so that we can maintain authorship

test/integration/targets/command_shell/tasks/main.yml

@@ -121,35 +121,6 @@
     that:
       - "command_result4.changed != True"
 
-
-- name: pass stdin to cat via command
-  command: "cat"
-  args:
-    stdin: 'foobar'
-  register: command_result5
-
-- name: assert that stdin is passed
-  assert:
-    that:
-      - "command_result5.stdout == 'foobar'"
-
-- name: send to stdin literal multiline block
-  command: "{{ sha1sum.stdout }}"
-  args:
-    stdin: |-
-      this is the first line
-      this is the second line
-      this line is after an empty line
-      this line is the last line
-  register: command_result6
-
-- debug: var=command_result6
-
-- name: assert the multiline input was passed correctly
-  assert:
-    that:
-      - "command_result6.stdout == 'b1a4df888d8d261876dc33ded211ba3ebe803010  -'"
-
 ##
 ## shell
 ##