increase Linux tool_integration_tests* subsharding (#164935)

The last subshard of Linux tool_integration_test is timing out again:
https://ci.chromium.org/ui/p/flutter/builders/luci.flutter.prod/Linux%20tool_integration_tests_6_6

This increases the subsharding to get the tree to a healthy state


<details>

<summary> Pre-launch checklist </summary> 


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there for submitting PRs.
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responsibilities.
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we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

</details>


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Author: andrewkolos

.ci.yaml

@@ -1239,7 +1239,8 @@ targets:
       - engine/**
       - DEPS
 
-  - name: Linux tool_integration_tests_1_6
+  - name: Linux tool_integration_tests_1_7
+    bringup: true
     recipe: flutter/flutter_drone
     timeout: 60
     properties:
@@ -1255,7 +1256,7 @@ targets:
           {"dependency": "open_jdk", "version": "version:17"}
         ]
       shard: tool_integration_tests
-      subshard: "1_6"
+      subshard: "1_7"
       tags: >
         ["framework", "hostonly", "shard", "linux"]
       test_timeout_secs: "2700"
@@ -1267,7 +1268,8 @@ targets:
       - engine/**
       - DEPS
 
-  - name: Linux tool_integration_tests_2_6
+  - name: Linux tool_integration_tests_2_7
+    bringup: true
     recipe: flutter/flutter_drone
     timeout: 60
     properties:
@@ -1283,7 +1285,7 @@ targets:
           {"dependency": "open_jdk", "version": "version:17"}
         ]
       shard: tool_integration_tests
-      subshard: "2_6"
+      subshard: "2_7"
       tags: >
         ["framework", "hostonly", "shard", "linux"]
       test_timeout_secs: "2700"
@@ -1295,7 +1297,8 @@ targets:
       - engine/**
       - DEPS
 
-  - name: Linux tool_integration_tests_3_6
+  - name: Linux tool_integration_tests_3_7
+    bringup: true
     recipe: flutter/flutter_drone
     timeout: 60
     properties:
@@ -1311,7 +1314,7 @@ targets:
           {"dependency": "open_jdk", "version": "version:17"}
         ]
       shard: tool_integration_tests
-      subshard: "3_6"
+      subshard: "3_7"
       tags: >
         ["framework", "hostonly", "shard", "linux"]
       test_timeout_secs: "2700"
@@ -1323,7 +1326,8 @@ targets:
       - engine/**
       - DEPS
 
-  - name: Linux tool_integration_tests_4_6
+  - name: Linux tool_integration_tests_4_7
+    bringup: true
     recipe: flutter/flutter_drone
     timeout: 60
     properties:
@@ -1339,7 +1343,7 @@ targets:
           {"dependency": "open_jdk", "version": "version:17"}
         ]
       shard: tool_integration_tests
-      subshard: "4_6"
+      subshard: "4_7"
       tags: >
         ["framework", "hostonly", "shard", "linux"]
       test_timeout_secs: "2700"
@@ -1351,7 +1355,8 @@ targets:
       - engine/**
       - DEPS
 
-  - name: Linux tool_integration_tests_5_6
+  - name: Linux tool_integration_tests_5_7
+    bringup: true
     recipe: flutter/flutter_drone
     timeout: 60
     properties:
@@ -1367,7 +1372,7 @@ targets:
           {"dependency": "open_jdk", "version": "version:17"}
         ]
       shard: tool_integration_tests
-      subshard: "5_6"
+      subshard: "5_7"
       tags: >
         ["framework", "hostonly", "shard", "linux"]
       test_timeout_secs: "2700"
@@ -1379,7 +1384,37 @@ targets:
       - engine/**
       - DEPS
 
-  - name: Linux tool_integration_tests_6_6
+  - name: Linux tool_integration_tests_6_7
+    bringup: true
+    recipe: flutter/flutter_drone
+    timeout: 60
+    properties:
+      add_recipes_cq: "true"
+      dependencies: >-
+        [
+          {"dependency": "android_sdk", "version": "version:35v1"},
+          {"dependency": "chrome_and_driver", "version": "version:125.0.6422.141"},
+          {"dependency": "clang", "version": "git_revision:5d5aba78dbbee75508f01bcaa69aedb2ab79065a"},
+          {"dependency": "cmake", "version": "build_id:8787856497187628321"},
+          {"dependency": "goldctl", "version": "git_revision:2387d6fff449587eecbb7e45b2692ca0710b63b9"},
+          {"dependency": "ninja", "version": "version:1.9.0"},
+          {"dependency": "open_jdk", "version": "version:17"}
+        ]
+      shard: tool_integration_tests
+      subshard: "6_7"
+      tags: >
+        ["framework", "hostonly", "shard", "linux"]
+      test_timeout_secs: "2700"
+    runIf:
+      - dev/**
+      - packages/flutter_tools/**
+      - bin/**
+      - .ci.yaml
+      - engine/**
+      - DEPS
+
+  - name: Linux tool_integration_tests_7_7
+    bringup: true
     recipe: flutter/flutter_drone
     timeout: 60
     properties:
@@ -1395,7 +1430,7 @@ targets:
           {"dependency": "open_jdk", "version": "version:17"}
         ]
       shard: tool_integration_tests
-      subshard: "6_6"
+      subshard: "7_7"
       tags: >
         ["framework", "hostonly", "shard", "linux"]
       test_timeout_secs: "2700"