[tools] Various system-analyzer fixes

- Handle empty script sources
- Fix list-panel groups, order by count

Bug: v8:10644
Change-Id: I03d3915f709d47429040b591c0271e951eca58e9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3289642
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Auto-Submit: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Patrick Thier <pthier@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78165}

tools/profile.mjs

@@ -70,7 +70,7 @@ export class SourcePosition {
 
 export class Script {
   url;
-  source;
+  source = "";
   name;
   sourcePosition = undefined;
   // Map<line, Map<column, SourcePosition>>
@@ -106,7 +106,7 @@ export class Script {
   }
 
   findFunctionSourcePosition(sourcePosition) {
-    // TODO(cbruni) implmenent
+    // TODO(cbruni): implement
     return undefined;
   }
 

tools/system-analyzer/helper.mjs

@@ -102,6 +102,6 @@ export function groupBy(array, keyFunction, collect = false) {
     groups.push(group);
     keyToGroup.set(key, group);
   }
-  // Sort by count
-  return groups.sort((a, b) => b.count - a.count);
-}
\ No newline at end of file
+  // Sort by length
+  return groups.sort((a, b) => b.length - a.length);
+}

tools/system-analyzer/view/list-panel.mjs

@@ -112,6 +112,7 @@ DOM.defineCustomElement('view/list-panel',
 
   createSubgroups(group) {
     const map = new Map();
+    const tempGroups = [];
     for (let propertyName of this._propertyNames) {
       map.set(
           propertyName,
@@ -176,9 +177,6 @@ DOM.defineCustomElement('view/list-panel',
   _render(groups, table) {
     let last;
     new LazyTable(table, groups, group => {
-      if (last && last.count < group.length) {
-        console.log(last, group);
-      }
       last = group;
       const tr = DOM.tr();
       tr.group = group;