[PGO][test] Specify exact match for check labels

Some check labels in the basic.ll test are simply f[1-3], which matches
all cases where the function entry is hot, cold, or uncategorized.
Since the actual test results for each label have mixed cases, the
current labels can be considered ambiguous.

This patch specifies exact matches for each label to ensure more precise
validation and to prevent potential regressions in the future.

Author: Ken Matsui

llvm/test/Analysis/ProfileSummary/basic.ll

@@ -5,27 +5,27 @@
 
 define void @f1() !prof !20 {
 ; CHECK-LABEL: f1 :hot
-; OVERRIDE-HOT-LABEL: f1
+; OVERRIDE-HOT-LABEL: f1{{$}}
 ; OVERRIDE-COLD-LABEL: f1 :hot
-; OVERRIDE-BOTH-LABEL: f1
+; OVERRIDE-BOTH-LABEL: f1{{$}}
 
   ret void
 }
 
 define void @f2() !prof !21 {
 ; CHECK-LABEL: f2 :cold
 ; OVERRIDE-HOT-LABEL: f2 :cold
-; OVERRIDE-COLD-LABEL: f2
-; OVERRIDE-BOTH-LABEL: f2
+; OVERRIDE-COLD-LABEL: f2{{$}}
+; OVERRIDE-BOTH-LABEL: f2 :cold
 
   ret void
 }
 
 define void @f3() !prof !22 {
-; CHECK-LABEL: f3
-; OVERRIDE-HOT-LABEL: f3
-; OVERRIDE-COLD-LABEL: f3
-; OVERRIDE-BOTH-LABEL: f3
+; CHECK-LABEL: f3 :hot
+; OVERRIDE-HOT-LABEL: f3{{$}}
+; OVERRIDE-COLD-LABEL: f3 :hot
+; OVERRIDE-BOTH-LABEL: f3 :cold
 
   ret void
 }