Convert angle dEQP tests to standalone.

Sample approximate summed test run improvements:

win-angle-deqp-rel-64:
100 shards, 300 minutes -> 27 shards, 50 minutes

win-angle-deqp-rel-32:
8 shards, 45 minutes -> 2 shards, 5 minutes

linux-angle-rel:
70 shards, 80 minutes -> 21 shards, 27 minutes

Android should be unchanged. In total this may save almost
6 hours of bot time per ANGLE CQ run.

Bug: angleproject:5124
Change-Id: I3be354058e32293c1360a2ed279666ecf19e41fe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2454401
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818745}

testing/buildbot/gn_isolate_map.pyl

@@ -1531,6 +1531,41 @@
     "label": "//sql:sql_unittests",
     "type": "console_test_launcher",
   },
+  "standalone_angle_deqp_egl_tests": {
+    "label": "//third_party/angle/src/tests:standalone_angle_deqp_egl_tests",
+    "type": "script",
+    "script": "//third_party/angle/scripts/run_gtest_angle_test.py",
+  },
+  "standalone_angle_deqp_gles2_tests": {
+    "label": "//third_party/angle/src/tests:standalone_angle_deqp_gles2_tests",
+    "type": "script",
+    "script": "//third_party/angle/scripts/run_gtest_angle_test.py",
+  },
+  "standalone_angle_deqp_gles31_tests": {
+    "label": "//third_party/angle/src/tests:standalone_angle_deqp_gles31_tests",
+    "type": "script",
+    "script": "//third_party/angle/scripts/run_gtest_angle_test.py",
+  },
+  "standalone_angle_deqp_gles3_tests": {
+    "label": "//third_party/angle/src/tests:standalone_angle_deqp_gles3_tests",
+    "type": "script",
+    "script": "//third_party/angle/scripts/run_gtest_angle_test.py",
+  },
+  "standalone_angle_deqp_khr_gles2_tests": {
+    "label": "//third_party/angle/src/tests:standalone_angle_deqp_khr_gles2_tests",
+    "type": "script",
+    "script": "//third_party/angle/scripts/run_gtest_angle_test.py",
+  },
+  "standalone_angle_deqp_khr_gles3_tests": {
+    "label": "//third_party/angle/src/tests:standalone_angle_deqp_khr_gles3_tests",
+    "type": "script",
+    "script": "//third_party/angle/scripts/run_gtest_angle_test.py",
+  },
+  "standalone_angle_deqp_khr_gles31_tests": {
+    "label": "//third_party/angle/src/tests:standalone_angle_deqp_khr_gles31_tests",
+    "type": "script",
+    "script": "//third_party/angle/scripts/run_gtest_angle_test.py",
+  },
   "standalone_angle_end2end_tests": {
     "label": "//third_party/angle/src/tests:standalone_angle_end2end_tests",
     "script": "//third_party/angle/scripts/run_gtest_angle_test.py",