* [RZ/A1H]Support RTX v4.80 for Cortex-A and a few Malloc API

PR to update RTX to v4.80 for Cortex-A.
In the latest CI test, three tests result in an error. The cause is mainly three points
- Unsupport RTX v4.80 for Cortex-A
- Insufficient stack size of thread defined in test
- A few Lack of Malloc API in GCC
Therefore, I supported to these. For the stack size for test, @Russ already supported in PR #3362.

Reference for issue of test error is here.
https://github.com/ARMmbed/mbed-os/issues/3273

Reference for PR to update RTX for Cortex-M.
https://github.com/ARMmbed/mbed-os/pull/1702

* Revert "[RZ/A1H]Support RTX v4.80 for Cortex-A and a few Malloc API"

This reverts commit e71f79a.

* [RZ/A1H]Support RTX v4.80 for Cortex-A and a few Malloc API

PR to update RTX to v4.80 for Cortex-A.
In the latest CI test, three tests result in an error. The cause is mainly three points
- Unsupport RTX v4.80 for Cortex-A
- Insufficient stack size of thread defined in test
- A few Lack of Malloc API in GCC
Therefore, I supported to these. For the stack size for test, @c1728p9 already supported in PR #3362.

Reference for issue of test error is here.
https://github.com/ARMmbed/mbed-os/issues/3273

Reference for PR to update RTX for Cortex-M.
https://github.com/ARMmbed/mbed-os/pull/1702