proposed new Mips specific directories in test-suite

I would like to add some subdirectories to test-suite



There are a lot of Mips specific tests.

For Mips16/32 interoperability, some of these require multiple source files.

The corresponding Makefiles would be changed to add these directories when $(ARCH)=MIPS

We , at Mips, would take ownership of these subdirectories so we can add tests that are relevant to the Mips port.