AndroidRuntime: reduce logcat debug spam

this ought to prevent log messages similar to:
D/AndroidRuntime(12391):
D/AndroidRuntime(12391): >>>>>> AndroidRuntime START com.android.internal.os.RuntimeInit <<<<<<
D/AndroidRuntime(12391): CheckJNI is OFF

Change-Id: Ie6948daf552d138c97ade941bedb8714f03145a3
Remove java.io.tmpdir assignment in AndroidRuntime.

This value is overridden by the framework anyway
(see ActivityThread.handleBindApplication). Besides,
it doesn't seem like a great idea to let tools clutter
/sdcard/ with temp files.

Change-Id: I26c710cbea7397f89e6103e54a73044a87da95b1
Remove unused field from AssetManager.

This field was introduced in commit 4bdd33b81a17 but wasn't
used there (or since).

Change-Id: I0615e98b8990d42da6b85f8094ab19eb0465fd9e
Remove stray logging statement.

bug: https://code.google.com/p/android/issues/detail?id=66974
Change-Id: Ie34c102de143cf6aeb16c78778dda3ef5e928380
Don't allow MemoryFiles of negative length.

Prevents us from converting a (signed) jint into an
(unsigned) size_t and having horrible things happen.

Change-Id: I0f04e2eb9852ae7fc49b435fd0974f56e86751a4
Fix preference puts with "null" values.

Null values were being written out as <null /> elements in the
XML prefs file (as expected). This allowed the getFoo() functions
to work correctly because they treated null values as missing mappings
but containsKey would fail.

bug: https://code.google.com/p/android/issues/detail?id=64563
Change-Id: I1f466d01db96bf26e208d4fed3a6f257228bea5d