[llvm] [msan] Switch to -msan-handle-icmp-exact my default (PR #113200)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ml-opt-dev-x86-64` running on `ml-opt-dev-x86-64-b2` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/137/builds/7368

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: Instrumentation/MemorySanitizer/pr32842.ll' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 4: /b/ml-opt-dev-x86-64-b1/build/bin/opt < /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/Instrumentation/MemorySanitizer/pr32842.ll -S -passes=msan 2>&1 | /b/ml-opt-dev-x86-64-b1/build/bin/FileCheck /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/Instrumentation/MemorySanitizer/pr32842.ll
+ /b/ml-opt-dev-x86-64-b1/build/bin/opt -S -passes=msan
+ /b/ml-opt-dev-x86-64-b1/build/bin/FileCheck /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/Instrumentation/MemorySanitizer/pr32842.ll
/b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/Instrumentation/MemorySanitizer/pr32842.ll:18:15: error: CHECK-NEXT: is not on the line after the previous match
; CHECK-NEXT: [[TMP28:%.*]] = shl i32 [[TMP0]], 1
              ^
<stdin>:28:2: note: 'next' match was here
 %8 = shl i32 %0, 1
 ^
<stdin>:21:29: note: previous match ended here
 call void @llvm.donothing()
                            ^
<stdin>:22:1: note: non-matching line after previous match is here
 %2 = shl i32 %1, 1
^

Input file: <stdin>
Check file: /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/Instrumentation/MemorySanitizer/pr32842.ll

-dump-input=help explains the following input dump.

Input was:
<<<<<<
         .
         .
         .
        23:  %3 = lshr i32 %2, 1 
        24:  %4 = xor i32 %1, %3 
        25:  %5 = xor i32 %4, -1 
        26:  %6 = and i32 %y, %5 
        27:  %7 = or i32 %6, %3 
        28:  %8 = shl i32 %0, 1 
next:18      !~~~~~~~~~~~~~~~~~  error: match on wrong line
        29:  %9 = lshr i32 %8, 1 
        30:  %10 = xor i32 %0, %9 
        31:  %11 = xor i32 %9, -1 
        32:  %12 = and i32 %x, %11 
        33:  %13 = or i32 %12, %10 
         .
         .
         .
>>>>>>

--

...

```

</details>

https://github.com/llvm/llvm-project/pull/113200