Remove the fixed-length buffer in DdmHandleNativeHeap.getLeakInfo.

It was possible to overrun this buffer, and even if you did fill
the buffer in a single read and exit the loop, the "string" still
wouldn't be terminated.

Bug: 8468088
Change-Id: Ia19f4d26dfd79e7b63807a7ec9540b932163d246
Correct executable bit for source files [Take 2]

Change Ieb51bafb46c895a21d2e83696f5a901ba752b2c5 left out some
files, this fixes them.

Change-Id: Ia949a8581668836ea0251602e048f09c852f5169