[Sparc][Leon] Errata fixes for various errata in different versions of the...

[Sparc][Leon] Errata fixes for various errata in different versions of the Leon variants of the Sparc 32 bit processor.

The nature of the errata are listed in the comments preceding the errata fix passes. Relevant unit tests are implemented for each of these.

These changes update older versions of these errata fixes with improvements to code and unit tests.

Differential Revision: https://reviews.llvm.org/D21960

llvm-svn: 278489