[CIR][NFCI] Represent Complex RValues As Single Value

[mmha]

This patch removes one mlir::Value in the RValue class that has been used to represent complex values in classic CG. In CIR we plan on representing complex as a single value. It also removes some now unnecessary member functions related to complex handling.

[AmrDeveloper]

LGTM, Thanks!

[andykaylor]

Looks good to me!

[llvm-ci]

LLVM Buildbot has detected a new failure on builder clang-arm64-windows-msvc running on linaro-armv8-windows-msvc-04 while building clang at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/161/builds/6612

Here is the relevant piece of the build log for the reference

Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM-Unit :: Testing/Support/./TestingSupportTests.exe/0/3' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:C:\Users\tcwg\llvm-worker\clang-arm64-windows-msvc\build\unittests\Testing\Support\.\TestingSupportTests.exe-LLVM-Unit-11216-0-3.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=3 GTEST_SHARD_INDEX=0 C:\Users\tcwg\llvm-worker\clang-arm64-windows-msvc\build\unittests\Testing\Support\.\TestingSupportTests.exe
--

Script:
--
C:\Users\tcwg\llvm-worker\clang-arm64-windows-msvc\build\unittests\Testing\Support\.\TestingSupportTests.exe --gtest_filter=TempPathTest.TempDir
--
C:/Users/tcwg/llvm-worker/clang-arm64-windows-msvc/llvm-project/llvm/unittests/Testing/Support/TempPathTest.cpp(40): error: Value of: sys::fs::exists(Path)
  Actual: true
Expected: false


C:/Users/tcwg/llvm-worker/clang-arm64-windows-msvc/llvm-project/llvm/unittests/Testing/Support/TempPathTest.cpp:40
Value of: sys::fs::exists(Path)
  Actual: true
Expected: false



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