[NFC][LoopUnroll] Add `-unroll-runtime-other-exit-predictable=false` in `runtime-multiexit-heuristic.ll`

[Whitney]

Summary

Added -unroll-runtime-other-exit-predictable=false in runtime-multiexit-heuristic.ll to make it more robust.
runtime-multiexit-heuristic.ll intention is to test -unroll-runtime-multi-exit=false, so the default value of -unroll-runtime-other-exit-predictable should not impact the result.

[Meinersbur]

LGTM

llvm/test/Transforms/LoopUnroll/runtime-multiexit-heuristic.ll

-; RUN: opt < %s -loop-unroll -unroll-runtime=true -verify-dom-info -verify-loop-info -instcombine -S | FileCheck %s
-; RUN: opt < %s -loop-unroll -unroll-runtime=true -verify-dom-info -unroll-runtime-multi-exit=false -verify-loop-info -S | FileCheck %s -check-prefix=NOUNROLL
+; RUN: opt < %s -unroll-runtime-other-exit-predictable=false -loop-unroll -unroll-runtime=true -verify-dom-info -verify-loop-info -instcombine -S | FileCheck %s
+; RUN: opt < %s -unroll-runtime-other-exit-predictable=false -loop-unroll -unroll-runtime=true -verify-dom-info -unroll-runtime-multi-exit=false -verify-loop-info -S | FileCheck %s -check-prefix=NOUNROLL
 
 ; this tests when unrolling multiple exit loop occurs by default (i.e. without specifying -unroll-runtime-multi-exit)
 
 ; the second exit block is a deopt block. The loop has one exiting block other than the latch.
 define i32 @test1(i32* nocapture %a, i64 %n) {
 ; CHECK-LABEL: test1(
 ; CHECK-LABEL:  header.epil:
 ; CHECK-NEXT:     %indvars.iv.epil = phi i64 [ %indvars.iv.next.epil, %latch.epil ], [ %indvars.iv.unr, %header.epil.preheader ]