Revert "Fix kv parsing bug in greentea client."

[0xc0170]

Summary of changes

This reverts commit c70baa9.

Reason for revert: needs to be reviewed again, will be sent via new PR. This reverts part of #13210

I reverted only one commit as the other one in the PR is logically different one so did not see any connection between them and should work on master (test fix).

cc @dustin-crossman @jamesbeyond

Impact of changes

Migration actions required

Documentation

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Pull request type

[x] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[x] No Tests required for this change (E.g docs only update)
[] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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Reviewers

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[mbed-ci]

Test run: SUCCESS

Summary: 6 of 6 test jobs passed
Build number : 1
Build artifacts