[test] Reduce time spent on js-perf tests and fix timeouts.

test/js-perf-test/JSTests.json

 {
   "name": "JSTests",
-  "run_count": 5,
-  "run_count_android_arm": 3,
-  "run_count_android_arm64": 3,
+  "run_count": 3,
+  "run_count_android_arm": 1,
+  "run_count_android_arm64": 1,
   "timeout": 120,
   "units": "score",
   "total": true,
   "resources": ["base.js"],
   "tests": [
     {
       "name": "Generators",
       "path": ["Generators"],
       "main": "run.js",
       "resources": ["generators.js"],
@@ skipping 22 matching lines @@
         "--turbo",
         "--turbo-from-bytecode"
       ],
       "results_regexp": "^Generators\\-Generators\\(Score\\): (.+)$"
     },
     {
       "name": "RestParameters",
       "path": ["RestParameters"],
       "main": "run.js",
       "resources": ["rest.js"],
-      "run_count": 5,
       "units": "score",
       "results_regexp": "^%s\\-RestParameters\\(Score\\): (.+)$",
       "tests": [
         {"name": "Basic1"}
       ]
     },
     {
       "name": "SpreadCalls",
       "path": ["SpreadCalls"],
       "main": "run.js",
       "resources": ["spreadcalls.js"],
-      "run_count": 5,
       "units": "score",
       "results_regexp": "^%s\\-SpreadCalls\\(Score\\): (.+)$",
       "tests": [
         {"name": "Call"},
         {"name": "CallMethod"},
         {"name": "CallNew"}
       ]
     },
     {
       "name": "Classes",
@@ skipping 41 matching lines @@
       "tests": [
         {"name": "ForOf"}
       ]
     },
     {
       "name": "Strings",
       "path": ["Strings"],
       "main": "run.js",
       "resources": ["harmony-string.js"],
       "results_regexp": "^%s\\-Strings\\(Score\\): (.+)$",
+      "run_count": 1,
+      "timeout": 240,
       "tests": [
         {"name": "StringFunctions"}
       ]
     },
     {
       "name": "StringIterators",
       "path": ["StringIterators"],
       "main": "run.js",
       "resources": ["string-iterator.js"],
       "results_regexp": "^%s\\-StringIterators\\(Score\\): (.+)$",
       "tests": [
         {"name": "Spread_OneByteShort"},
         {"name": "Spread_TwoByteShort"},
         {"name": "Spread_WithSurrogatePairsShort"},
         {"name": "ForOf_OneByteShort"},
         {"name": "ForOf_TwoByteShort"},
         {"name": "ForOf_WithSurrogatePairsShort"},
         {"name": "ForOf_OneByteLong"},
         {"name": "ForOf_TwoByteLong"},
         {"name": "ForOf_WithSurrogatePairsLong"}
       ]
     },
     {
       "name": "Templates",
       "path": ["Templates"],
       "main": "run.js",
       "resources": ["templates.js"],
-      "run_count": 5,
       "units": "score",
       "results_regexp": "^%s\\-Templates\\(Score\\): (.+)$",
       "total": true,
       "tests": [
         {"name": "Untagged"},
         {"name": "LargeUntagged"},
         {"name": "Tagged"}
       ]
     },
     {
@@ skipping 34 matching lines @@
       "tests": [
         {"name": "Try-Catch"}
       ]
     },
     {
       "name": "Keys",
       "path": ["Keys"],
       "main": "run.js",
       "resources": ["keys.js"],
       "results_regexp": "^%s\\-Keys\\(Score\\): (.+)$",
-      "run_count": 3,
-      "run_count_android_arm": 2,
-      "run_count_android_arm64": 2,
       "tests": [
         {"name": "Object.keys()"},
         {"name": "for-in"},
         {"name": "for-in hasOwnProperty()"},
         {"name": "for (i < Object.keys().length)"},
         {"name": "Object.keys().forEach()"},
         {"name": "for (i < array.length)"},
         {"name": "for (i < length)"}
       ]
     },
@@ skipping 15 matching lines @@
         {"name": "Object.hasOwnProperty--DEINTERN-prop"},
         {"name": "Object.hasOwnProperty--NE-INTERN-prop"},
         {"name": "Object.hasOwnProperty--NE-DEINTERN-prop"},
         {"name": "Object.hasOwnProperty--el"},
         {"name": "Object.hasOwnProperty--el-str"},
         {"name": "Object.hasOwnProperty--NE-el"}
       ]
     }
   ]
 }