[InstCombine] Add test cases for 'or' and 'xor' to match the vector 'and' of 'sext...

[InstCombine] Add test cases for 'or' and 'xor' to match the vector 'and' of 'sext' of 'cmp' test.

When the 'and' test was originally added it was intended to make sure we didn't change it to a sext of and of cmp. But since then the test was changed to expect it to be turned into 'select cmp1, sext cmp2, 0'. Then another optimization was added to turn the select into 'sext (and cmp1, cmp2)' which is exactly the transformation that was being blocked when the test case started.

Looks like 'or' gets optimized in a similar way, but not 'xor'.

llvm-svn: 309793