[RISCV][NFC] Simplify SLP vectorization tests

llvm/test/Transforms/SLPVectorizer/RISCV/load-store.ll

 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -passes=slp-vectorizer -mtriple=riscv64 -mattr=+v \
-; RUN: -riscv-v-vector-bits-min=-1 -riscv-v-slp-max-vf=0 -S | FileCheck %s --check-prefixes=CHECK
-; RUN: opt < %s -passes=slp-vectorizer -mtriple=riscv64 -mattr=+v -S | FileCheck %s --check-prefixes=DEFAULT
+; RUN: -riscv-v-vector-bits-min=-1 -riscv-v-slp-max-vf=0 -S | FileCheck %s
+; RUN: opt < %s -passes=slp-vectorizer -mtriple=riscv64 -mattr=+v -S | FileCheck %s --check-prefix=DEFAULT
 
 
 define void @simple_copy(ptr %dest, ptr %p) {
 ; CHECK-LABEL: @simple_copy(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[TMP0:%.*]] = load <2 x i16>, ptr [[P:%.*]], align 4
 ; CHECK-NEXT:    store <2 x i16> [[TMP0]], ptr [[DEST:%.*]], align 4
 ; CHECK-NEXT:    ret void

llvm/test/Transforms/SLPVectorizer/RISCV/reductions.ll

 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -passes=slp-vectorizer -mtriple=riscv64 -mattr=+v \
-; RUN: -riscv-v-vector-bits-min=128 -S | FileCheck %s --check-prefixes=CHECK
+; RUN: -riscv-v-vector-bits-min=128 -S | FileCheck %s
 ; RUN: opt < %s -passes=slp-vectorizer -mtriple=riscv64 -mattr=+v \
-; RUN: -riscv-v-vector-bits-min=256 -S | FileCheck %s --check-prefixes=CHECK
+; RUN: -riscv-v-vector-bits-min=256 -S | FileCheck %s
 ; RUN: opt < %s -passes=slp-vectorizer -mtriple=riscv64 -mattr=+v \
-; RUN: -riscv-v-vector-bits-min=512 -S | FileCheck %s --check-prefixes=CHECK
+; RUN: -riscv-v-vector-bits-min=512 -S | FileCheck %s
 
 target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n64-S128"
 target triple = "riscv64"
 
 ; First batch of tests are simple reductions of various widths
 
 define i64 @red_ld_2xi64(ptr %ptr) {
 ; CHECK-LABEL: @red_ld_2xi64(