Remove two tests from platform dependent tests (#10017)

Summary:
Platform dependent tests sometimes run too long and causes timeout in Travis. Remove two tests that are less likely to be platform dependent.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10017

Test Plan: Watch Travis tests.

Reviewed By: pdillinger

Differential Revision: D36486734

fbshipit-source-id: 2a3ad1746791c893a790c2a69a3b70f81e7de260

Makefile

@@ -632,7 +632,6 @@ TESTS_PLATFORM_DEPENDENT := \
 	db_basic_test \
 	db_blob_basic_test \
 	db_encryption_test \
-	db_test2 \
 	external_sst_file_basic_test \
 	auto_roll_logger_test \
 	bloom_test \
@@ -654,7 +653,6 @@ TESTS_PLATFORM_DEPENDENT := \
 	rate_limiter_test \
 	perf_context_test \
 	iostats_context_test \
-	db_wal_test \
 
 # Sort ROCKSDBTESTS_SUBSET for filtering, except db_test is special (expensive)
 # so is placed first (out-of-order)