Bug 1366644 - Part 3a: Update Android build-tools (25.0.3), Gradle (3.4.1), Android-Gradle (2.3.3). r=maliu The goal is to use a newer Android-Gradle build plugin version (2.3.3 is latest stable). That requires a modern Gradle (anything 3.3+, but 3.4.1 is the default from my Android Studio), and also a newer build-tools (25.0.3 is latest stable). The locations of lint output changed, and we want to use the standard output location because it's difficult to accommodate variant details in custom names. We change the location of findbugs output to follow suit. This requires either: - fixing lint errors - adding to the lint whitelist - using the new lint baseline It's best to use the new lint baseline, which will happen in the next commit. MozReview-Commit-ID: D19FzIDCJrE

# Checks run by clang-tidy over Mozilla code.

# The following checks are currently enabled:
# * modernize-raw-string-literal -
#     Replace string literals containing escaped characters with raw string literals
# * modernize-use-bool-literals
#     Replace integer literals which are cast to bool
# * modernize-loop-convert
#     Converts for(...; ...; ...) loops to use the new range-based loops in C++11
# * modernize-use-default
#     Replace default bodies of special member functions with = default;
# * modernize-use-override
#     Use C++11's override and remove virtual where applicable

Checks:          '-*, modernize-raw-string-literal, modernize-use-bool-literals, modernize-loop-convert, modernize-use-default, modernize-use-override'