RFR (S) 8228630: Remove always true parameter to NoSafepointVerifier

[coleen.phillimore at oracle.com]

Summary: Also remove NoGCVerifier since NoSafepointVerifier covers GC 
checking when not already at a safepoint and is a stronger check.

See bug for more details also.  Tested with all jtreg 
runtime,compiler,serviceability and gc tests.  Also hs-tier1-3 on 
linux-x64-debug.

open webrev at http://cr.openjdk.java.net/~coleenp/2019/8228630.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8228630

Thanks,
Coleen