As seen in bug 713196, it looks like when you run a large test suite split across multiple shards, we log the file location for every test in a compiled binary, rather than just the tests we actually run. 

In addition, we list every test in the binary in the "all_tests" field, rather than just the tests we run.

And, it looks like the test location is actually probably wrong (or at least useless), regardless, i.e. the entries are of the form:

"dEQP_GLES3.Default/functional_attribute_location_bind_float": {
         "file": "e:\\b\\c\\b\\win\\src\\third_party\\angle\\src\\tests\\deqp_support\\angle_deqp_gtest.cpp",
         "line": 380
      },
      "dEQP_GLES3.Default/functional_attribute_location_bind_hole_float": {
         "file": "e:\\b\\c\\b\\win\\src\\third_party\\angle\\src\\tests\\deqp_support\\angle_deqp_gtest.cpp",
         "line": 380
      },

where every test has the same file location.

As a result, the log from a single test invocation is 15MB of JSON. It looks like we're running into trouble merging this data together across 10 shards.

Sergiy, can you please look into this ASAP and see what you can do to (a) make the file smaller and (b) get the locations right or disable this info if we can't?