[RISCV] Add missing CHECK prefix to fixed-vectors-vfw-web-simplification.ll. NFC

The FOLDING prefix was ambiguous on one of the test cases. It would be
nice if the update script reported this.

Author: topperc

llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vfw-web-simplification.ll

@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -mtriple=riscv64 -mattr=+v,+zfh,+zvfh,+f,+d -verify-machineinstrs %s -o - --riscv-lower-ext-max-web-size=1 | FileCheck %s --check-prefixes=NO_FOLDING
 ; RUN: llc -mtriple=riscv64 -mattr=+v,+zfh,+zvfh,+f,+d -verify-machineinstrs %s -o - --riscv-lower-ext-max-web-size=2 | FileCheck %s --check-prefixes=NO_FOLDING
-; RUN: llc -mtriple=riscv64 -mattr=+v,+zfh,+zvfh,+f,+d -verify-machineinstrs %s -o - --riscv-lower-ext-max-web-size=3 | FileCheck %s --check-prefixes=FOLDING
+; RUN: llc -mtriple=riscv64 -mattr=+v,+zfh,+zvfh,+f,+d -verify-machineinstrs %s -o - --riscv-lower-ext-max-web-size=3 | FileCheck %s --check-prefixes=FOLDING,ZVFH
 ; RUN: llc -mtriple=riscv64 -mattr=+v,+zfh,+zvfhmin,+f,+d -verify-machineinstrs %s -o - --riscv-lower-ext-max-web-size=3 | FileCheck %s --check-prefixes=FOLDING,ZVFHMIN
 ; Check that the default value enables the web folding and
 ; that it is bigger than 3.
@@ -23,6 +23,17 @@ define void @vfwmul_v2f116_multiple_users(ptr %x, ptr %y, ptr %z, <2 x half> %a,
 ; NO_FOLDING-NEXT:    vse32.v v8, (a2)
 ; NO_FOLDING-NEXT:    ret
 ;
+; ZVFH-LABEL: vfwmul_v2f116_multiple_users:
+; ZVFH:       # %bb.0:
+; ZVFH-NEXT:    vsetivli zero, 2, e16, mf4, ta, ma
+; ZVFH-NEXT:    vfwmul.vv v11, v8, v9
+; ZVFH-NEXT:    vfwadd.vv v12, v8, v10
+; ZVFH-NEXT:    vfwsub.vv v8, v9, v10
+; ZVFH-NEXT:    vse32.v v11, (a0)
+; ZVFH-NEXT:    vse32.v v12, (a1)
+; ZVFH-NEXT:    vse32.v v8, (a2)
+; ZVFH-NEXT:    ret
+;
 ; ZVFHMIN-LABEL: vfwmul_v2f116_multiple_users:
 ; ZVFHMIN:       # %bb.0:
 ; ZVFHMIN-NEXT:    vsetivli zero, 2, e16, mf4, ta, ma