[TensorExpr] Add log1p support to the LLVM backend (#44839)
Summary:
Also corrected Sleef_log1p registrations, float versions had a redundant f.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44839
Test Plan: test_tensorexpr --gtest_filter=TensorExprTest.LLVMElemwiseLog1pFloat_LLVM
Reviewed By: glaringlee
Differential Revision: D23762113
Pulled By: asuhan
fbshipit-source-id: b5cf003b5c0c1ad549c7f04470352231929ac459
