Now that googletest can print ConstantRange, use EXPECT_EQ when testing for

Now that googletest can print ConstantRange, use EXPECT_EQ when testing for
equality. Prefer EXPECT_EQ(foo, Full) over EXPECT_TRUE(foo.isFullSet()) because
the former will print out the contents of the constant range that failed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81094 91177308-0d34-0410-b5e6-96231b3b80d8