[SLP][X86] slp-fma-loss.ll - add various targets with different FMA abilities

Add targets with FMA3, FMA4 and no-FMA support

Should help with D132872 testing

Author: RKSimon

llvm/test/Transforms/SLPVectorizer/X86/slp-fma-loss.ll

@@ -1,5 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -passes=slp-vectorizer -S -mcpu=core-avx2 -mtriple=x86_64-unknown-linux-gnu -slp-threshold=-2 < %s | FileCheck %s
+; RUN: opt -passes=slp-vectorizer -S -mcpu=corei7 -mtriple=x86_64-unknown-linux-gnu -slp-threshold=-2 < %s | FileCheck %s --check-prefixes=CHECK
+; RUN: opt -passes=slp-vectorizer -S -mcpu=bdver2 -mtriple=x86_64-unknown-linux-gnu -slp-threshold=-2 < %s | FileCheck %s --check-prefixes=CHECK
+; RUN: opt -passes=slp-vectorizer -S -mcpu=core-avx2 -mtriple=x86_64-unknown-linux-gnu -slp-threshold=-2 < %s | FileCheck %s  --check-prefixes=CHECK
 
 ; This test checks for a case when a horizontal reduction of floating-point
 ; adds may look profitable, but is not because it eliminates generation of