[CIR][ThroughMLIR] Add support for almabench and fbench from SingleSource test suite.

[goxul]

From the SingleSource test suite, almabench had a missing ATan2 implemention, whereas fbench had missing asin support. This PR adds support for both.

1. A lowering for ATan2 is added via ThroughMLIR.
2. NYI for Asin changed with the appropriate invocation.

[goxul]

With this, both the tests pass.

/Documents/test-suite/build main % llvm-lit --timeout=60 -v SingleSource/Benchmarks/Misc/fbench.test SingleSource/Benchmarks/CoyoteBench/almabench.test 
llvm-lit: /Users/gokulnathp/Documents/llvm-project/llvm/utils/lit/lit/main.py:72: note: The test suite configuration requested an individual test timeout of 0 seconds but a timeout of 60 seconds was requested on the command line. Forcing timeout to be 60 seconds.
-- Testing: 2 tests, 2 workers --
PASS: test-suite :: SingleSource/Benchmarks/Misc/fbench.test (1 of 2)
********** TEST 'test-suite :: SingleSource/Benchmarks/Misc/fbench.test' RESULTS **********
compile_time: 0.0675 
exec_time: 0.4681 
hash: "d677e99cc79e1f469b0f24b59dcb1e2a" 
link_time: 0.0615 
size: 50568 
size.__bss: 1216 
size.__common: 4 
size.__const: 64 
size.__cstring: 201 
size.__data: 4 
size.__eh_frame: 176 
size.__got: 88 
size.__stubs: 132 
size.__text: 2336 
size.__unwind_info: 96 
**********
PASS: test-suite :: SingleSource/Benchmarks/CoyoteBench/almabench.test (2 of 2)
********** TEST 'test-suite :: SingleSource/Benchmarks/CoyoteBench/almabench.test' RESULTS **********
compile_time: 0.0670 
exec_time: 1.6678 
hash: "e8b207d5b71848a2b5d279ae6563ad28" 
link_time: 0.0726 
size: 34168 
size.__const: 4906 
size.__eh_frame: 264 
size.__got: 72 
size.__stubs: 96 
size.__text: 4028 
size.__unwind_info: 112 
**********

Testing Time: 1.88s

Total Discovered Tests: 2
  Passed: 2 (100.00%)

Not sure if this enables some more test cases as well.

[bcardosolopes]

No need for an extra newline here

[bcardosolopes]

While here, please add lowering and a test for direct LLVM lowering.

[bcardosolopes]

Thanks for working on this @goxul.

Please change the title to be about the actual adding of ATan2, etc. You can add more information about the benchmarks in the description. Question: I wasn't expecting all these benchmarks to be working in the throughMLIR path, are you sure this is what you are running? Anyways, if direct LLVM also is missing this lowering, please go ahead and add it as part of this PR.