[system health] Fix wpr archive names.

tools/perf/page_sets/data/system_health_mobile.json

 {
     "archives": {
-        "memory_system_health_mobile_000.wpr": [
+        "system_health_mobile_000.wpr": [
             "load:search:amazon",
             "load:search:baidu",
             "load:search:yandex",
             "load:search:google",
             "load:search:taobao",
             "load:search:ebay",
             "load:search:yahoo"
         ],
-        "memory_system_health_mobile_001.wpr": [
+        "system_health_mobile_001.wpr": [
             "load:social:tumblr",
             "load:social:pinterest",
             "load:social:instagram"
         ],
-        "memory_system_health_mobile_002.wpr": [
+        "system_health_mobile_002.wpr": [
             "load:news:sohu",
             "load:news:bbc",
             "load:news:wikipedia"
         ],
-        "memory_system_health_mobile_003.wpr": [
+        "system_health_mobile_003.wpr": [
             "load:media:9gag",
             "load:media:google_images",
             "load:media:soundcloud",
             "load:media:youtube",
             "load:media:dailymotion",
             "load:media:flickr"
         ],
-        "memory_system_health_mobile_004.wpr": [
+        "system_health_mobile_004.wpr": [
             "load:tools:gmail",
             "load:tools:maps",
             "load:tools:stackoverflow",
             "load:tools:dropbox",
             "load:tools:weather",
             "load:tools:drive",
             "load:tools:docs"
         ],
-        "memory_system_health_mobile_005.wpr": [
+        "system_health_mobile_005.wpr": [
             "load:games:lazors",
             "load:games:bubbles",
             "load:games:spychase"
         ],
-        "memory_system_health_mobile_006.wpr": [
+        "system_health_mobile_006.wpr": [
             "load:news:cnn"
         ],
-        "memory_system_health_mobile_007.wpr": [
+        "system_health_mobile_007.wpr": [
             "load:social:facebook"
         ],
-        "memory_system_health_mobile_008.wpr": [
+        "system_health_mobile_008.wpr": [
             "load:news:hackernews"
         ],
-        "memory_system_health_mobile_009.wpr": [
+        "system_health_mobile_009.wpr": [
             "load:news:nytimes"
         ],
-        "memory_system_health_mobile_010.wpr": [
+        "system_health_mobile_010.wpr": [
             "load:news:qq"
         ],
-        "memory_system_health_mobile_011.wpr": [
+        "system_health_mobile_011.wpr": [
             "load:news:reddit"
         ],
-        "memory_system_health_mobile_012.wpr": [
+        "system_health_mobile_012.wpr": [
             "load:social:twitter"
         ],
-        "memory_system_health_mobile_013.wpr": [
+        "system_health_mobile_013.wpr": [
             "load:news:washingtonpost"
         ],
-        "browsing_mobile_000.wpr": [
+        "system_health_mobile_014.wpr": [
             "browse:news:cnn"
         ],
-        "browsing_mobile_001.wpr": [
+        "system_health_mobile_015.wpr": [
             "browse:social:facebook"
         ],
-        "browsing_mobile_002.wpr": [
+        "system_health_mobile_016.wpr": [
             "browse:news:hackernews"
         ],
-        "browsing_mobile_003.wpr": [
+        "system_health_mobile_017.wpr": [
             "browse:news:nytimes"
         ],
-        "browsing_mobile_004.wpr": [
+        "system_health_mobile_018.wpr": [
             "browse:news:qq"
         ],
-        "browsing_mobile_005.wpr": [
+        "system_health_mobile_019.wpr": [
             "browse:news:reddit"
         ],
-        "browsing_mobile_006.wpr": [
+        "system_health_mobile_020.wpr": [
             "browse:social:twitter"
         ],
-        "browsing_mobile_007.wpr": [
+        "system_health_mobile_021.wpr": [
             "browse:news:washingtonpost"
         ]
     },
     "description": "Describes the Web Page Replay archives for a story set. Don't edit by hand! Use record_wpr for updating."
 }