[UMA] Fix misconfigured histogram suffix

A previous change to rename a histogram missed the suffix declaration.
This change changes the suffix to refer to the renamed histogram.

Bug: 842023
Change-Id: I97f0f8ae7e3cc48d4bfbb820ada67ec5088a0cdc
Reviewed-on: https://chromium-review.googlesource.com/1075514Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: Mohamed Heikal <mheikal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562457}

tools/metrics/histograms/histograms.xml

@@ -109615,10 +109615,8 @@ uploading your change for review.
   <suffix name="Tabbed"
       label="Chrome starts up with intent to ChromeTabbedActivity"/>
   <suffix name="WebApk" label="Chrome starts up with intent to WebApkActivity"/>
-  <affected-histogram
-      name="Startup.Android.Experimental.Cold.TimeToFirstContentfulPaint"/>
-  <affected-histogram
-      name="Startup.Android.Experimental.Cold.TimeToFirstNavigationCommit"/>
+  <affected-histogram name="Startup.Android.Cold.TimeToFirstContentfulPaint"/>
+  <affected-histogram name="Startup.Android.Cold.TimeToFirstNavigationCommit"/>
 </histogram_suffixes>
 
 <histogram_suffixes name="AdsPageLoadMetrics" separator="." ordering="prefix">