Do not sleep while waiting for GC

This is a partial revert of aosp/1690649. It backs out the
addition of the wait loop in CheckGCForNative().

We can apparently still encounter cases in which we sleep for a
nonexistent GC.

Test: Build and boot AOSP
Bug: 187531176
Bug: 186592536
Change-Id: Icaf75ae3582ea51eecf9fe4b81e629bc1d862788
1 file changed