Auto merge of #3089 - kozyilmaz:clang, r=str4d

[macOS] Fix test/gtest bugs caught by latest clang

Tests fail with latest clang on macOS (clang-900.0.39.2)

```
test/rpc_wallet_tests.cpp:1064:26: error: implicit conversion from 'double' to 'CAmount' (aka 'long long') changes value from 123.456 to 123 [-Werror,-Wliteral-conversion]
test/rpc_wallet_tests.cpp:1071:18: error: implicit conversion from 'double' to 'CAmount' (aka 'long long') changes value from 1.111 to 1 [-Werror,-Wliteral-conversion]
gtest/test_deprecation.cpp:28:1: error: control reaches end of non-void function [-Werror,-Wreturn-type]
```

Part of #2246.

diff --cc src/test/rpc_wallet_tests.cpp
Simple merge