[8u] Revert Shenandoah-specific assert after JDK-8211926 landed

[Aleksey Shipilev]

Shenandoah-specific assert is not needed anymore, after all relevant backports landed upstream. This
reverts bitMap.inline.hpp to 8u upstream state.

diff -r 37c96d78c3c2 src/share/vm/utilities/bitMap.inline.hpp
--- a/src/share/vm/utilities/bitMap.inline.hpp  Wed Jul 17 18:09:43 2019 +0200
+++ b/src/share/vm/utilities/bitMap.inline.hpp  Thu Jul 18 18:22:04 2019 +0200
@@ -322,10 +322,10 @@

 inline void BitMap::set_large_range_of_words(idx_t beg, idx_t end) {
-  assert(!UseShenandoahGC || (beg <= end), "underflow"); // Make sure Shenandoah does not blow up
on JDK-8211926
+  assert(beg <= end, "underflow");
   memset(_map + beg, ~(unsigned char)0, (end - beg) * sizeof(uintptr_t));
 }

 inline void BitMap::clear_large_range_of_words(idx_t beg, idx_t end) {
-  assert(!UseShenandoahGC || (beg <= end), "underflow"); // Make sure Shenandoah does not blow up
on JDK-8211926
+  assert(beg <= end, "underflow");
   memset(_map + beg, 0, (end - beg) * sizeof(uintptr_t));
 }

Testing: hotspot_gc_shenandoah

Thanks,
-Aleksey