[test] Auto-detect verify-predictable builds

Bug: v8:6917
Change-Id: Ia768c9aaf71e70d1376ae21a35fd539a7315b0cd
Reviewed-on: https://chromium-review.googlesource.com/725802
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48717}

BUILD.gn

@@ -849,6 +849,7 @@ action("v8_dump_build_config") {
     "is_ubsan_vptr=$is_ubsan_vptr",
     "target_cpu=\"$target_cpu\"",
     "v8_enable_i18n_support=$v8_enable_i18n_support",
+    "v8_enable_verify_predictable=$v8_enable_verify_predictable",
     "v8_target_cpu=\"$v8_target_cpu\"",
     "v8_use_snapshot=$v8_use_snapshot",
   ]

src/v8.gyp

@@ -2557,6 +2557,7 @@
             'is_ubsan_vptr=0',
             'target_cpu="<(target_arch)"',
             'v8_enable_i18n_support=<(v8_enable_i18n_support)',
+            'v8_enable_verify_predictable=<(v8_enable_verify_predictable)',
             'v8_target_cpu="<(v8_target_arch)"',
             'v8_use_snapshot=<(v8_use_snapshot)',
           ],

tools/testrunner/base_runner.py

@@ -317,6 +317,7 @@ class BaseTestRunner(object):
       ('msan', build_config["is_msan"]),
       ('no_i18n', not build_config["v8_enable_i18n_support"]),
       ('no_snap', not build_config["v8_use_snapshot"]),
+      ('predictable', build_config["v8_enable_verify_predictable"]),
       ('tsan', build_config["is_tsan"]),
       ('ubsan_vptr', build_config["is_ubsan_vptr"]),
     ):