adb: remove win32 dependency on libwinpthread-1.dll.

Explicitly link against the static libwinpthread.a to avoid a
dependency on the dll.

Also, make the tests link against libbase statically.

Bug: http://b/31665213
Test: wine adb.exe
Test: wine adb_test.exe
Change-Id: Ifd41afcb1756a4b9b6db12e102b4db502e73d846