Revert "Time out and dump stacks from R8 processes after 30 minutes"

This reverts commit 29c294b2.

The deadlock in R8 was fixed, and the timeout causes problems when
RBE is enabled and the R8 action gets stuck in a queue for 30
minutes.

Bug: 207767452
Test: checkbuild
Change-Id: Ia0c3826aea3288e9db3bdbd4955e1e16c0a38fe3
Merged-In: Ia0c3826aea3288e9db3bdbd4955e1e16c0a38fe3
(cherry picked from commit a832a04d)